2A2J3-SR23Smart Ring

Thank you for choosing Cardio Ring. We want you to get the most out of your experience. Therefore, please read this important information leaflet and the accompanying Quick Guide carefully before using your ring, mobile App and any other related services (Cardio Ring Services). Failure to follow the instructions below could result in product damage or malfunction, or even injury. Support and Questions If you have any questions about getting started with or using your ring, mobile App and any other Cardio Ring Services, or you have any issues with your product, please refer to the Frequently Asked Questions (FAQs) at (https://www.linktop.com). If you can’t find what you are looking for, send us an email to [email protected] . 1 Safety Information Please note that Cardio Ring Services are not intended to diagnose, treat, cure, or prevent any disease or medical condition. The information and guidance in the Cardio Ring Services are there for informational purposes only and cannot replace the services of health professionals or physicians. You should always consult a physician if you have any questions regarding any changes you intend to make to your sleep or activity based on information or guidance of the Cardio Ring Services, or regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on or through the Cardio Ring Services. 2 We are not responsible for any health problems that may result from information or guidance you learn about through the Cardio Ring Services. If you make any change to your sleep or activity based on the Cardio Ring Services, you agree that you do so fully at your own risk. It is important to be sensitive to your body’s responses. For example, if you feel unexpected, repeated or long term pain, fatigue or discomfort due to having made changes to your sleep or activity, it is recommended that you consult a physician before continuing with such changes. The information and guidance in the Cardio Ring Services may be misleading if your physiological functions and responses differ significantly from population averages due to medical conditions or rare natural differences. Please be cautious that the ring or any other Linktop product you are wearing does not get caught on fixed structures or heavy objects when moving yourself or moving said heavier objects. 3 Finger size can vary depending on the time of the day, and sometimes it may be difficult to remove the ring from your finger. In case the ring gets stuck: • Use cold water and gentle soap to wet your finger, and slowly twist the ring to remove it. • Hold your hand up above your heart until the blood pressure gets lower, and then try the removal. If you experience redness or skin irritation on your finger due to the ring or any other Linktop product, remove it immediately. If symptoms persist longer than 2-3 days of not using your Linktop product, please contact a dermatologist. Our Product should not be placed in the mouth at any time. Cardio Ring Product is not a toy nor is it intended for use by children. Children should not be left unattended with this Product, as it may pose a choking hazard. Use, care and maintenance 4 • In cases of emergency, cut the ring from the palm side of the finger, from its thinnest point with a ring cutter. This prevents cutting the battery. The lithium - ion polymer battery should not have electrolyte flowing, but in case electrolyte comes in contact with your skin or eyes, flush it out with water and seek immediate medical attention. Use soft cloth or hand wash with mild soap and water to clean the ring. 5 Cardio Ring can be worn in shower, when taking a bath or when swimming. It is even suitable for skin diving with snorkel. Try to avoid wearing the ring when strength training, working with a shovel or other heavy tools, or carrying heavy objects made of metal, ceramics or stone. In addition, try to avoid wearing the ring next to other rings or objects which are made of metal, ceramics or stones, like diamond. The Cardio Ring may get scratches or it can scratch softer metal jewelry or other objects in close contact with the ring, like phone covers, made of e. g. gold, silver, aluminum. Also some ceramic phone covers may get scratches, if covered with softer coating. Keep the ring away from children. Do not leave the ring exposed to heat, such as in a vehicle or in the sun. Do not puncture the ring or its battery. 6 The ring material is titanium. Like with all rings made of metals such as silver, gold or steel, be careful when handling batteries when you`re wearing the ring. In some rare cases where both the cathode and the anode of a battery touch the ring, there is a risk of battery short circuit, similar to normal metal rings without electronics in them. An electrocardiogram (ECG or EKG) is a test that records the timing and strength of electrical signals that make the heart beat. By looking at an ECG, a doctor can gain insights about your heart rhythm and look for irregularities. About Electrocardiograms 7 Four Things to Remember The app can check your heart rhythm for AFib and show your heart rate. There are some things to remember. • It cannot detect a heart attack. If you ever experience chest pain, pressure, tightness, or what you think is a heart attack, call emergency services immediately. • It cannot detect blood clots or a stroke. • It cannot detect other heart-related conditions. These include high blood pressure, congestive heart failure, high cholesterol, or other forms of arrhythmia. • If you are not feeling well you should talk to your doctor. 8 Results You May See (1) Sinus Rhythm A sinus rhythm result means the heart is beating in a uniform pattern. This happens when the upper and lower chambers of the heart are beating in sync. A sinus rhythm result only applies to that particular recording and doesn't mean your heart beats with a consistent pattern all the time. (2) Atrial Fibrillation …

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Xiamen Linktop Technology Co., Ltd. Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Federal Communications Commission Authorization and Evaluation Division Equipment Authorization Branch 7435 Oakland Mills Road Columbia, MD 21046 2024-7-13 To whom it may concern: We, Xiamen Linktop Technology Co., Ltd., hereby certify that the equipment for which authorization is sought (FCC ID: 2A2J3-SR23) is not “covered” equipment prohibited from receiving an equipment authorization pursuant to § 2.903 of the FCC rules. We also certify that, as of the date of the filing of the application, we are not identified on the Covered List (https://www.fcc.gov/supplychain/coveredlist) as an entity producing “covered” equipment. By signing this form, we confirm the above and that we are aware of the application requirements listed under § 2.911(b) and (d)(5) and (6). The information provided in this letter is based on the referenced rule parts of Title 47 of the CFR as well as KDB 986446 D01. Sincerely, Signature Rongfeng Fan Electrical Engineer Xiamen Linktop Technology Co., Ltd. 62_[model] CoveredEqu_2.911(d)(5)(i) and (ii) - U, V03

XiamenLinktopTechnologyCo.,Ltd. FederalCommunicationsCommission AuthorizationandEvaluationDivision EquipmentAuthorizationBranch 7435OaklandMillsRoad Columbia,MD21046 {July3,2024} U.S.AgentDesignation {XiamenLinktopTechnologyCo.,Ltd.}acknowledgestheirconsentforthefollowingcontactlocatedinthe UnitedStatestoactastheiragentforserviceofprocessfortheequipmentforwhichauthorizationissought (FCCID:2A2J3-SR23): NameandcompanyofU.S.agent:Nexvoo,Inc PhysicalU.S.addressofagent:1702WMichiganStIndianapolis,IN46222USAIndianapolis UnitedStates FRNofU.S.agent:0029792173 EmailaddressofU.S.agent:[email protected] {Nexvoo,Inc}acknowledgestheirobligationtoacceptserviceofprocessonbehalfof{XiamenLinktop TechnologyCo.,Ltd.}. {XiamenLinktopTechnologyCo.,Ltd.}withtheFRN[0031130610]acceptsitsobligationtomaintainanagent forserviceofprocessintheUnitedStatesfornolessthanoneyearaftereitherthegranteehaspermanently terminatedallmarketingandimportationoftheapplicableequipmentwithintheU.S.,ortheconclusionofany Commission-relatedadministrativeorjudicialproceedinginvolvingtheequipment,whicheverislater. Bysigningthisform,weconfirmtheaboveandthatweareawareoftheapplicationrequirementslistedunder§ 2.911(d)(7). TheinformationprovidedinthisletterisbasedonthereferencedrulepartsofTitle47oftheCFRaswellasKDB 986446D01. Anexpirationdateforthisletterdoesnotexist.IncasetheU.S.agentchanges,thegranteeisobligatedtonotify theFCCwithin30daysviathegrantingTCB. Sincerely, Signature {RongfengFan} {ElectricalEngineer} {XiamenLinktopTechnologyCo.,Ltd.} Signature {Sophiazhang} {ProjectManager} {Nexvoo,Inc} 4 8 _ [ m o d e l ] U S _ A g e n t _ 2 . 9 1 1 ( d ) ( 7 ) - U , V 0 5

Xiamen Linktop Technology Co., Ltd. Add: Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Date: 2024-7-13 FCC ID: 2A2J3-SR23 Dear Sir/Madam, We, Xiamen Linktop Technology Co., Ltd. Hereby declares the following statement for Federal Communications Commission, PCB board, circuit, structure and internal of these model(s) are the same, Only model number is different for these model: Product name: Smart Ring Model no.: SR23, SR23B, SR23C, SR23D, SR26, SR26B, SR26C, SR26D, SR27, SR27B, SR27C, SR27D, SR28, SR28B, SR28C, SR28D Sincerely, Name/Title： Rongfeng Fan/Electrical Engineer Company: Xiamen Linktop Technology Co., Ltd. Address: Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Phone: 86-13860464623 Fax: 86-592-3691680 E-Mail: [email protected]

CONFIDENTIALITY REQUEST for Certification Service in USA Federal Communication Commission Equipment Authorization Division, Application Processing Branch 7435 Oakland Mills Road Columbia, MD 21046 Date:<2024-7-13> Pursuant to Paragraphs §0.457 and 0.459 of the Commission’s Rules (47 C.F.R.) and Section §552(b)(4) of the Freedom of Information Act, we requests confidentiality for the following products: FCC ID Model name 2A2J3-SR23 SR23 For the product stated above, we request that the following information be held confidential; Exhibits Long-Term Confidentiality Short-Term Confidentiality Short-Term Confidentiality Days External Photos Internal Photos Block Diagram Schematics Test Setup Photos User’s Manual Parts List Tune Up Operational Descriptions The long-term confidentiality exhibits contain our trade secrets and proprietary information that could be of benefit to our competitors. The short-term confidentiality on the basis of ensuring that business sensitive information remains confidential until the actual marketing of our new device. If you have any questions, please feel free to contact me at the address shown below. Sincerely, Name/Title： Rongfeng Fan/Electrical Engineer Company: Xiamen Linktop Technology Co., Ltd. Address: Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Phone: 86-13860464623 Fax: 86-592-3691680 E-Mail: [email protected]

Xiamen Linktop Technology Co., Ltd. Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Federal Communications Commission Authorization and Evaluation Division Equipment Authorization Branch 7435 Oakland Mills Road Columbia, MD 21046 2024-7-13 To whom it may concern: We, the undersigned, hereby authorize Eurofins Product Service GmbH to act on our behalf in all matters relating to applications for equipment authorization FCC ID: 2A2J3-SR23 including the signing of all documents related to these matters. Any and all acts carried out by Eurofins Product Service GmbH on our behalf shall have the same effect as acts of our own. By signing this application form, we agree to Eurofins’ current valid General Terms and Conditions (AGB),Testing and Certification Regulations (PZO) which can be viewed on following website www.eurofins.de/ee or retrieved on request. We also hereby certify that no party to this application is subject to a denial of benefits, including FCC benefits, pursuant to Section 5301 of the Anti-Drug Abuse Act of 1988, 21 U.S.C. 862. Sincerely, Name/Title： Rongfeng Fan/Electrical Engineer Company: Xiamen Linktop Technology Co., Ltd. Address: Room 501-2,502,503, North Building, Torch Hi-Tech Zone, No.56-58 Huoju Road Xiamen,Fujian China Phone: 86-13860464623 Fax: 86-592-3691680 E-Mail: [email protected]

FCCID:2A2J3-SR23 FCCID:2A2J3-SR23 FCCID:2A2J3-SR23 FCCID:2A2J3-SR23

Note:Asthesizeoftheequipmentistoosmall,thelabelwasputintheusermanualandpackaging.

FCCID:2A2J3-SR23 FCCID:2A2J3-SR23

Page1of2 RFEXPOSUREEVALUATION FCCID:2A2J3-SR23 Modeldifference: Onlytheappearancecolorandmodelnamearedifferent. ProductName:SmartRing ModelName:SR23 Serialmodel: SR23B,SR23C,SR23D,SR26,SR26B,SR26C,SR26D,SR27,SR27B, SR27C,SR27D,SR28,SR28B,SR28C,SR28D Specification:BluetoothBLE Operatingfrequency:2402-2480MHz NumbersofChannel:40channelsForDTS AntennaType:PCBantenna AntennaGain:0.95dBi TypeofModulation:GFSK Powersupply: Input:DC5V Lithiumprimarybattery:170724 RatedVoltage:3.7V HardwareVersion:2.3 SoftwareVersion:1.0.0 Page2of2 StandardRequirement Accordingto§15.247(i)and§1.1307b(1),systemsoperatingundertheprovisionsofthis sectionshallbeoperatedinamannerthatensuresthatthepublicisnotexposedtoradio frequencyenergylevelsinexcessoftheCommission’sguidelines.SeeKDB447498D01 GeneralRFExposureGuidancev06,section4.3.1. The1-gand10-gSARtestexclusionthresholdsfor100MHzto6GHzattestseparation distances≤50mmaredeterminedby: [(max.powerofchannel,includingtune-uptolerance,mW)/(min.testseparationdistance, mm)]*[√f(GHz)]≤3.0for1-gSARand≤7.5for10-gSARextremitySAR,where f(GHz)istheRFchanneltransmitfrequencyinGHz PoweranddistanceareroundedtothenearestmWandmmbeforecalculation Theresultisroundedtoonedecimalplaceforcomparison. Thetestexclusionsareapplicableonlywhentheminimumtestseparationdistanceis≤ 50mmandfortransmissionfrequenciesbetween100MHzand6GHz.Whentheminimumtest separationdistanceis<5mm,adistanceof5mmisappliedtodetermineSARtestexclusion. RoutineSARevaluationreferstothatspecificallyrequiredby§2.1093,usingmeasurements orcomputersimulation.WhenroutineSARevaluationisnotrequired,portabletransmitters withoutputpowergreaterthantheapplicablelowthresholdrequireSARevaluationtoquality forTCBapproval. Channel (MHz) Maximum output power (dBm) Tuneup tolerance (dBm) MaxTune UpPower (mW) Distance (mm) Calculation results Limit Operating Mode 24021.72 1.72±1 1.87068250.5798513BLE AccordingtoKDB447498,nostand-alonerequiredforBTantenna,andnosimultaneousSAR measurementisrequired. Signature SimonPu Manager Date:2024-06-28

PCB antenna specification 1. Product model PCB antenna 2. Features *Stable and reliable in performances *Low temperature coefficient of frequency *Low profile, compact size *RoHS compliance 3.Applications *Bluetooth earphone systems *Hand-held devices when Bluetooth functions are needed, e.g., Smart phone. 4. Description The antenna are specially designed for Bluetooth applications. Based on proprietary design and processes,this antenna has excellent stability and sensitivity to consistently provide high signal reception efficiency 5. Electrical Specifications 5-1 Characteristics Specifications Unit Outline Dimensions 5.6×8.5 mm Working Frequency 2442 MHz Bandwidth (under -10dB return loss) 100min MHz VSWR 2MAX. Impedance 50 Ω Polarization Linear Polarization Gain** Peak 0.95（typical） dBi Efficiency 84（typical） % Temperature Coefficient of Frequency 0±20max（@-40°C~85°C） ppm/°C ** Working frequency will be offset to another frequency according to the conditions of users ground plane and radome. **The data was measured by A Test Lab Techno Corp.(CTIA Authorized Test Lab). 5-2 6. Antenna Dimensions(unit:mm) a.AntennaDimensions 7.Radiation Pattern 7-1.3D Gain Pattern at（2442MHz） 5.78mm 2.78mm 7-2. Efficiency Table Z X Y Frequency(MHz) 2400 2410 2420 2430 2442 2450 2460 2470 2480 2490 2500 Efficiency（dB） -1.38 -1.04 -0.85 -0.74 -0.73 -0.76 -0.86 -1.05 -1.18 -1.27 -1.40 Efficiency（%） 72.83 78.71 82.27 84.39 84.53 84.04 82.00 78.60 76.14 74.64 72.50 Gain（dBi） 0.55 0.6 0.71 0.82 0.95 0.95 0.8 0.69 0.65 0.63 0.59 7-3.Efficiency vs.Frequency 8. Matching circuit: 9. Fine tuning element vs. Center frequency System Matching Circuit Component Location Description Vendor 1 N/A - 2 2.2uH (0402) 3 0.7PF 0402 10.Storage Conditions: 1) Temperature:-25 to 85 (2) Relative Humidity:20% to 70%

Page1of52 FCCTESTREPORT FCCID:2A2J3-SR23 Product: SmartRing ModelName:SR23 Serialmodel: SR23B,SR23C,SR23D,SR26,SR26B,SR26C,SR26D, SR27,SR27B,SR27C,SR27D,SR28,SR28B,SR28C, SR28D Brand: N/A ReportNo.: PTC24052500701E-FC01 Preparedfor XiamenLinktopTechnologyCo.,Ltd. Room501-2,502,503,NorthBuilding,TorchHi-TechZone,No.56-58Huoju Road,Xiamen,Fujian,China Preparedby PreciseTesting&CertificationCo.,Ltd Building1,No.6,TongxinRoad,DongchengStreet,Dongguan,Guangdong,China ReportNo.:PTC24052500701E-FC01 Page2of52 1TESTRESULTCERTIFICATION Applicant’sname:XiamenLinktopTechnologyCo.,Ltd. Address: Room501-2,502,503,NorthBuilding,TorchHi-TechZone,No.56-58 HuojuRoad,Xiamen,Fujian,China Manufacture'sname:XiamenLinktopTechnologyCo.,Ltd. Address: Room501-2,502,503,NorthBuilding,TorchHi-TechZone,No.56-58 HuojuRoad,Xiamen,Fujian,China Productname:SmartRing Modelname:SR23 Serialmodel: SR23B,SR23C,SR23D,SR26,SR26B,SR26C,SR26D,SR27, SR27B,SR27C,SR27D,SR28,SR28B,SR28C,SR28D Standards:FCCCFR47Part15Section15.247 Testprocedure:ANSIC63.10:2013 TestDate:Jun.24,2024toJun.28,2024 DateofIssue:Jun.28,2024 TestResult:Pass ThisdevicedescribedabovehasbeentestedbyPTC,andthetestresultsshowthatthe equipmentundertest(EUT)isincompliancewiththeFCCrequirements.Anditisapplicableonlyto thetestedsampleidentifiedinthereport. Thisreportshallnotbereproducedexceptinfull,withoutthewrittenapprovalofPTC,thisdocument maybealteredorrevisedbyPTC,personalonly,andshallbenotedintherevisionofthedocument. TestEngineer: Jackzhou/Engineer TechnicalManager: SimonPu/Manager ReportNo.:PTC24052500701E-FC01 Page3of52 Contents Page 1TESTRESULTCERTIFICATION...............................................................................................................................2 2TESTSUMMARY..........................................................................................................................................................5 2.1TESTSITE............................................................................................................................................................6 3GENERALINFORMATION.......................................................................................................................................7 3.1GENERALDESCRIPTIONOFE.U.T.....................................................................................................................7 3.2CHANNELLIST.....................................................................................................................................................7 4EQUIPMENTDURINGTEST....................................................................................................................................9 4.1EQUIPMENTSLIST.............................................................................................................................................9 4.2MEASUREMENTUNCERTAINTY.........................................................................................................................11 4.3DESCRIPTIONOFSUPPORTUNITS...................................................................................................................12 5CONDUCTEDEMISSION..........................................................................................................................................13 5.1E.U.T.OPERATION............................................................................................................................................13 5.2EUTSETUP.......................................................................................................................................................13 5.3TESTSET-UP(BLOCKDIAGRAMOFCONFIGURATION).................................................................................14 5.4MEASUREMENTPROCEDURE............................................................................................................................14 5.5CONDUCTEDEMISSIONLIMIT...........................................................................................................................14 5.6MEASUREMENTDESCRIPTION..........................................................................................................................14 5.7CONDUCTEDEMISSIONTESTRESULT.............................................................................................................14 6RADIATEDSPURIOUSEMISSIONS......................................................................................................................15 6.1EUTOPERATION...............................................................................................................................................17 6.2TESTSETUP......................................................................................................................................................18 6.3SPECTRUMANALYZERSETUP..........................................................................................................................19 6.4TESTPROCEDURE.............................................................................................................................................20 6.5SUMMARYOFTESTRESULTS...........................................................................................................................22 7CONDUCTBANDEDGEANDSPURIOUSEMISSIONSMEASUREMENT....................................................29 7.1TESTPROCEDURE.............................................................................................................................................29 7.2TESTSETUP......................................................................................................................................................29 7.3TESTRESULT....................................................................................................................................................30 ReportNo.:PTC24052500701E-FC01 Page4of52 86DBBANDWIDTHMEASUREMENT....................................................…

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FCCID:2A2J3-SR23 RadiatedSpuriousEmissions From30MHz-1000MHz Testfrequencyfrom1GHz