XEN-KBABB20MS20keys Bump Bar

Heng Yu Electronic Manufacturing Co. Ltd. Federal Communications Commission Authorization and Evaluation Division Equipment Authorization Branch 7435 Oakland Mills Road Columbia, MD 21046 [August 18, 2026] U.S. Agent Designation [Heng Yu Electronic Manufacturing Co. Ltd.] acknowledges their consent for the following contact located in the United States to act as their agent for service of process for the equipment for which authorization is sought FCC ID: XEN-KBABB20MS Name and company of U.S. agent: [GLOCERTS TECHNOLOGY INC] Physical U.S. address of agent: [19784 SUNKISSED RIDGE DR, RIVERSIDE, CA 92507] FRN of U.S. agent: [0036339737] Email address of U.S. agent: [[email protected]] Telephone of U.S.agent: (626) 588-8039 [GLOCERTS TECHNOLOGY INC] acknowledges their obligation to accept service of process on behalf of [Heng Yu Electronic Manufacturing Co. Ltd.]. [Heng Yu Electronic Manufacturing Co. Ltd.] with the FRN [0018800110] accepts its obligation to maintain an agent for service of process in the United States for no less than 1 year after either the grantee has permanently terminated all marketing and importation of the applicable equipment within the U.S., or the conclusion of any Commission-related administrative or judicial proceeding involving the equipment, whichever is later. By signing this form, we confirm the above and that we are aware of the application requirements listed under § 2.911(d)(7). 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 Signature [H.K. Chan] [Huiying Fan] [R&D Manager] [Director] [Heng Yu Electronic Manufacturing Co. Ltd.] [GLOCERTS TECHNOLOGY INC]

Heng Yu Electronic Manufacturing Co. Ltd. (August 18, 2026) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: Attestation Statements Part 2.911(d)(5)(i) request for FCC ID: XEN-KBABB20MS [Heng Yu Electronic Manufacturing Co. Ltd.] (“the applicant”) certifies that the equipment for which authorization is sought is not “covered” equipment prohibited from receiving an equipment authorization pursuant to section 2.903 of the FCC rules. We also certify that, as of the date of the filing of the application, the equipment does not utilize cyber-security or anti-virus software from Kaspersky Lab, Inc, or any of its successors and assignees, which is also on the “covered list”. Sincerely, (Applicant signature) (Applicant printed name) H.K. Chan Heng Yu Electronic Manufacturing Co. Ltd. (August 18, 2026) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: Attestation Statements Part 2.911(d)(5)(ii) request for FCC ID: XEN-KBABB20MS [Heng Yu Electronic Manufacturing Co. Ltd.] (“the applicant”) certifies that, as of the date of the filing of the application, the applicant is not identified on the Covered List as an entity producing “covered” equipment. Sincerely, (Applicant signature) (Applicant printed name) H.K. Chan

Heng Yu Electronic Manufacturing Co. Ltd. (August 18, 2026) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: CONFIDENTIALITY REQUEST FOR (20keys Bump Bar / KBA-BB20-MS / FCC ID: XEN-KBABB20MS) To Whom It May Concern: This letter serves as an official request for confidentiality under sections 0.457 and 0.459 of CFR 47. We have requested that the Exhibits Long-Term Confidentiality Short-Term Confidentiality NOTE 2 ID Label/Location No No Attestation Statement No No External Photos No ☐ Block Diagram ☒ ☐ Schematics ☒ ☐ Test Report No No Test Setup Photos No ☐ User’s Manual ☐ NOTE 1 ☒ Internal Photos ☐ NOTE 1 ☒ Parts List / Tune Up ☐ ☐ RF Exposure Info No No Operational Description ☒ ☐ Cover Letter(s) No No SDR Software / Security Info ☐ No required to be submitted with this application be permanently withheld from public review. Above mentioned document contains detailed system and equipment description are considered as proprietary information in operation of the equipment. The public disclosure of above documents might be harmful to our company and would give competitor an unfair advantage in the market. Please contact me if there is any information you may need. Sincerely, Signature: Name: H.K. Chan Title: R&D Manager

Heng Yu Electronic Manufacturing Co. Ltd. (September 4, 2026) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: LETTER OF AGENT AUTHORIZATION To Whom It May Concern: We, the undersigned, hereby authorize (Shenzhen NTT Testing Technology Co.,Ltd.) to act on our behalf in all matters relating to application for equipment authorization, including the signing of all documents relating to these matters. We also hereby certify that no party to the application authorized hereunder is subject to the denial of benefits, including FCC benefits, pursuant to Section 5301 of the Anti-Drug Abuse Act of 1988, 21 U.S.C.853(a). This agreement expires one year from the current date. Sincerely, Signature: Name: H.K. Chan Title: R&D Manager

FCC ID: XEN-KBABB20MS External Photos

FCC ID LABEL: Label Location:

Circuit Description KBA-BB20-MS 20keys Bump Bar uses CH571F chip. The whole protocol architecture can be divided into three parts: the bottom hardware module, the middle protocol layer and the high-end application layer. The external circuit consists of antenna RF matching circuit, 32MHz oscillation circuit, power filter circuit and output circuit, KEY function key PIO circuit and LED indicator lamp BLE: Operation Frequency: 2402-2480 MHz Modulation Type: GFSK Number Of Channel 40CH Antenna Designation: Bluetooth: PCB antenna Antenna Gain Bluetooth: 2.1dBi Ratings: DC 5V charging from notebook DC 3.0V by battery 2.4GHz Operation Frequency: 2402-2474MHz Modulation Type: GFSK Number Of Channel 37CH Antenna Designation: PCB antenna Antenna Gain 2.1dBi Ratings: DC 5V charging from notebook DC 3.0V by battery

FCC ID: XEN-KBABB20MS RF Exposure Evaluation According to KDB 447498 D01 General RF Exposure Guidance v06 and part 2.1093， Unless specifically required by the published RF exposure KDB procedures, standalone 1-g head or body and 10-g extremity SAR evaluation for general population exposure conditions, by measurement or numerical simulation, is not required when the corresponding SAR Test Exclusion Threshold condition(s), listed below, is (are) satisfied. For 100 MHz to 6 GHz and test separation distances ≤ 5 mm, the 1-g and 10-g SAR test exclusion thresholds are determined by the following: [(max. power of channel, including tune-up tolerance, mW) / (min. test separation distance, mm)] · [√f (GHz) ] ≤ 3.0 for 1-g SAR, and ≤ 7.5 for 10-g extremity SAR, where f (GHz) is the RF channel transmit frequency in GHz Power and distance are rounded to the nearest mW and mm before calculation The result is rounded to one decimal place for comparison Here, Remark：1. BT and 2.4GHz Antenna gain is 2.1dBi, So a SAR test is not required BLE Mode Freque ncy (MHz) Max Power (dBm) Target power W/ tolerance (dBm) Max tune up power tolerance (dBm) Max Power (mW) Min. Distance (mm) Calc. thresholds limit GFSK 2402 1.542 1±1 2.00 1.585 5 0.491 3.0 2440 1.67 1±1 2.00 1.585 5 0.495 3.0 2480 1.006 1±1 2.00 1.585 5 0.499 3.0 2.4GHz Mode Freque ncy (MHz) Max Power (dBm) Target power W/ tolerance (dBm) Max tune up power tolerance (dBm) Max Power (mW) Min. Distance (mm) Calc. thresholds limit GFSK 2402 1.738 1±1 2.00 1.585 5 0.491 3.0 2438 2.773 2±1 3.00 1.995 5 0.623 3.0 2474 2.428 2±1 3.00 1.995 5 0.628 3.0

PCB Antenna for BLE Chips of WCH 1、Dimension of Antenna 2、Features  Dimension: 5.6*12.3mm  Terminal impedance: 50 ohm  Max Gain: 2.1dBi  RF Frequency: 2.4GHz 3、S parameter Working bandwidth: 157MHz S11：[email protected] 4、Gain and Radiation pattern Max gain @2.4GHz: 2.08dBi E plane： H plane： Max Gain @2.44GHz: 2.1dBi E plane： H plane： Max Gain @2.48GHz: 2.04dBi E plane： H plane： Company and address of manufacturers: nanjing constant microelectronics co., LTD Address: Building C, Qinheng Science and Technology Park, No. 18, Ningshuang Road, Yuhua District, Nanjing City, Jiangsu Province

ShenzhenNTTTestingTechnologyCo.,Ltd.ReportNo.:SZNTT26035978E1-1 SZNTT-TR828-0Tel:0755-27889935Web:http://www.ntt-testing.comPage1of36 TESTREPORT Applicant: HengYuElectronicManufacturingCo.Ltd. Address: Room1503-5,NanFungCommercialCentre,19LamLoHongKong, China Manufacturer: ZhuhaiHengYuNewTechnologyCompanyLimited Address: No.10,YingyueRoad,SanzaoTown,JinwanDistrict,Zhuhai, Guangdong,P.R.China ProductName:20keysBumpBar ModelNumber:KBA-BB20-MS Trademark: N/A FCCID:XEN-KBABB20MS TestDate:Jun.25,2026toSep.02,2026 DateofReport:Jun.25,2026 TestResult: ThisdevicedescribedabovehasbeentestedbyNTT,andthetest resultsshowthattheequipmentundertest(EUT)isincompliance withtheStandardrequirements.Anditisapplicableonlytothetested sampleidentifiedinthereport. TestProcedureUsed: Standards:FCCCFRTitle47Part15SubpartCSection15.247 ANSIC63.10-2020+Cor.1-2023+C63.10a-2024+Erratato C63.10a-2024 KDB558074D0115.247MeasGuidancev05r02 Preparedby(TestEngineer): GaryLu Approved(Supervisor): CindyQin Approved(Manager): AbelYu ShenzhenNTTTestingTechnologyCo.,Ltd.ReportNo.:SZNTT26035978E1-1 SZNTT-TR828-0Tel:0755-27889935Web:http://www.ntt-testing.comPage2of36 TABLEOFCONTENT 1.GeneralInformation......................................................................................4 1.1.DescriptionofDevice(EUT).......................................................................................................................4 1.2.ChannelList..................................................................................................................................................4 1.3.Summaryoftestresult................................................................................................................................5 1.4.SpecialAccessoriesandAuxiliaryEquipment........................................................................................5 1.5.Testmode......................................................................................................................................................5 1.6.Testconfiguration.........................................................................................................................................5 1.7.BlockDiagram...............................................................................................................................................6 1.8.TestConditions.............................................................................................................................................6 1.9.MeasurementUncertainty(95%confidencelevels,k=2)......................................................................6 1.10.TestFacility..................................................................................................................................................7 1.11.TestEquipment...........................................................................................................................................8 2.Conductedemissionatthemainsterminalstest....................................10 2.1.Limit..............................................................................................................................................................10 2.2.TestSetup....................................................................................................................................................10 2.3.TestProcedure............................................................................................................................................10 2.4.TestResult...................................................................................................................................................11 3.RadiatedSpuriousEmissions...................................................................13 3.1.Limit..............................................................................................................................................................13 3.2.TestSetup....................................................................................................................................................14 3.3.TestProcedure............................................................................................................................................16 3.4.TestResult...................................................................................................................................................17 4.ConductedSpuriousEmissions................................................................22 4.1.Limit..............................................................................................................................................................22 4.2.TestSetup....................................................................................................................................................22 4.3.TestProcedure............................................................................................................................................22 4.4.TestResult...................................................................................................................................................23 5.BandEdgeMeasurement...........................................................................24 5.1.Limit..............................................................................................................................................................24 5.2.Testsetup....................................................................................................................................................24 5.3.TestProcedure............................................................................................................................................24 5.4.TestResult...................................................................................................................................................25 6.-6dBBandwidthand99%BandwidthMeasurem…

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ShenzhenNTTTestingTechnologyCo.,Ltd.ReportNo.:SZNTT26035978E1-2 SZNTT-TR828-0Tel:0755-27889935Web:http://www.ntt-testing.comPage1of36 TESTREPORT Applicant: HengYuElectronicManufacturingCo.Ltd. Address: Room1503-5,NanFungCommercialCentre,19LamLoHongKong, China Manufacturer: ZhuhaiHengYuNewTechnologyCompanyLimited Address: No.10,YingyueRoad,SanzaoTown,JinwanDistrict,Zhuhai, Guangdong,P.R.China ProductName:20keysBumpBar ModelNumber:KBA-BB20-MS Trademark: N/A FCCID:XEN-KBABB20MS TestDate:Jun.25,2026toSep.02,2026 DateofReport:Jun.25,2026 TestResult: ThisdevicedescribedabovehasbeentestedbyNTT,andthetest resultsshowthattheequipmentundertest(EUT)isincompliance withtheStandardrequirements.Anditisapplicableonlytothetested sampleidentifiedinthereport. TestProcedureUsed: Standards:FCCCFRTitle47Part15SubpartCSection15.247 ANSIC63.10-2020+Cor.1-2023+C63.10a-2024+Erratato C63.10a-2024 KDB558074D0115.247MeasGuidancev05r02 Preparedby(TestEngineer): GaryLu Approved(Supervisor): CindyQin Approved(Manager): AbelYu ShenzhenNTTTestingTechnologyCo.,Ltd.ReportNo.:SZNTT26035978E1-2 SZNTT-TR828-0Tel:0755-27889935Web:http://www.ntt-testing.comPage2of36 TABLEOFCONTENT 1.GeneralInformation......................................................................................4 1.1.DescriptionofDevice(EUT).......................................................................................................................4 1.2.ChannelList..................................................................................................................................................4 1.3.Summaryoftestresult................................................................................................................................5 1.4.SpecialAccessoriesandAuxiliaryEquipment........................................................................................5 1.5.Testmode......................................................................................................................................................5 1.6.Testconfiguration.........................................................................................................................................5 1.7.BlockDiagram...............................................................................................................................................6 1.8.TestConditions.............................................................................................................................................6 1.9.MeasurementUncertainty(95%confidencelevels,k=2)......................................................................6 1.10.TestFacility..................................................................................................................................................7 1.11.TestEquipment...........................................................................................................................................8 2.Conductedemissionatthemainsterminalstest....................................10 2.1.Limit..............................................................................................................................................................10 2.2.TestSetup....................................................................................................................................................10 2.3.TestProcedure............................................................................................................................................10 2.4.TestResult...................................................................................................................................................11 3.RadiatedSpuriousEmissions...................................................................13 3.1.Limit..............................................................................................................................................................13 3.2.TestSetup....................................................................................................................................................14 3.3.TestProcedure............................................................................................................................................16 3.4.TestResult...................................................................................................................................................17 4.ConductedSpuriousEmissions................................................................22 4.1.Limit..............................................................................................................................................................22 4.2.TestSetup....................................................................................................................................................22 4.3.TestProcedure............................................................................................................................................22 4.4.TestResult...................................................................................................................................................23 5.BandEdgeMeasurement...........................................................................24 5.1.Limit..............................................................................................................................................................24 5.2.Testsetup....................................................................................................................................................24 5.3.TestProcedure............................................................................................................................................24 5.4.TestResult...................................................................................................................................................25 6.-6dBBandwidthand99%BandwidthMeasurem…

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FCC ID: XEN-KBABB20MS Test Photos