2A9UW-DBSE-22DearBuds SE

■DearBudsManual 2A9UW-DBSE-22 DearBudsSE Spec. •Weight •Earbuds : 0.34oz/9.6g •Case : 0.42oz/11.9g •Size •Earbuds •W: 0.82in/20.71mm •L : 1.4in/35.67mm •H :1.33in/33.87mm •Case •W : 22.91mm •L : 37.88mm •H :30.67mm •Light •Dominant wavelength 631nm red LED •Luminous Intensity 18-54 mcd •Heat •Up to 100.4°F (38°C) •Air Delivery •Up to 3L/min •Connectivity •Bluetooth Low Energy wireless 2.4GHz •Sensors •High performance humidity sensor •Battery •Up to 24 times (soft) •Full charging for 2 hours •Silicone Ear-tips •Food grade silicone •Power •Li-ion Battery Charger : 3.0 ~ 4.2V •Operating Voltage : 3V DC MODEL No. :DBSE-22 FCC ID : 2A9UW-DBSE-22 KC ID : R-R-LFc-DBSE-22 MADE BY LINKFACE IN KOREA

Linkface Co., Ltd. 501-ho, 11, Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea Date: Oct 06, 2022 Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: CONFIDENTIALITY REQUEST FOR (DearBuds SE/DBSE-22/2A9UW-DBSE- 22) 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 (below list) required to be submitted with this application be permanently withheld from public review. Permanent Confidential Request -. Schematics -. Block Diagram -. Operational Description SPECIFY REASON FOR REQUEST (i.e. the above documents are company proprietary information that could never get into the possession of your competition). Please contact me if there is any information you may need. Sincerely, Kyungsoo Lim/ CEO

Linkface Co., Ltd. 501-ho, 11, Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea Date: Oct 06, 2022 Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: CONFIDENTIALITY REQUEST FOR (DearBuds SE/DBSE-22/2A9UW-DBSE- 22) 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 (below list) required to be submitted with this application be short-term Confidentiality for a period of 180 days after grant is issued. Short-Term Confidential Request -. External Photos -. Internal Photos -. Test set-up photo -. User Manual SPECIFY REASON FOR REQUEST (i.e. These documents contain detailed system and equipment descriptions and related information about the product, which we considers to be proprietary, confidential, and a custom design and otherwise, would not release to the general public. Since this design is a basis from which future technological products will evolve, we feel that this information would be of benefit to our competitors, and that the disclosure of the information in these documents would give our competitors an unfair advantage in the market. Please contact me if there is any information you may need. Sincerely, Kyungsoo Lim/ CEO

Linkface Co., Ltd. 501-ho, 11, Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea Date: Oct 06, 2022 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 Ms. Lena Lim / Assistant Manager o f Eurofins KCTL 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, Sincerely, Kyungsoo Lim / CEO

This document shall not be reproduced, except in full, without the written approval External photos of EUT This document shall not be reproduced, except in full, without the written approval This document shall not be reproduced, except in full, without the written approval

■Label info. & Location MODEL No. :DBSE-22 FCC ID : 2A9UW-DBSE-22 KC ID : R-R-LFc-DBSE-22 MADE BY LINKFACE IN KOREA

This document shall not be reproduced, except in full, without the written approval Internal photos of EUT This document shall not be reproduced, except in full, without the written approval Bluetooth LE Antenna This document shall not be reproduced, except in full, without the written approval

This test report shall not be reproduced, except in full, without the written approval * RF Exposure FCC ID: 2A9UW-DBSE-22 1. Regulation According to the KDB 447498 D01 V06, the following RF exposure evaluation shall to demonstrate RF exposure compliance. 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. These test exclusion conditions are based on source-based time-averaged maximum conducted output power of the RF channel requiring evaluation, adjusted for tune-up tolerance, and the minimum test separation distance required for the exposure conditions. The minimum test separation distance defined in 4.1 f) is determined by the smallest distance from the antenna and radiating structures or outer surface of the device, according to the host form factor, exposure conditions and platform requirements, to any part of the body or extremity of a user or bystander. To qualify for SAR test exclusion, the test separation distances applied must be fully explained and justified, typically in the SAR measurement or SAR analysis report, by the operating configurations and exposure conditions of the transmitter and applicable host platform requirements, according to the required published RF exposure KDB procedures. When no other RF exposure testing or reporting are required, a statement of justification and compliance must be included in the equipment approval, in lieu of the SAR report, to qualify for SAR test exclusion. When required, the device specific conditions described in the other published RF exposure KDB procedures must be satisfied before applying these SAR test exclusion provisions; for example, handheld PTT two-way radios, handsets, laptops and tablets, etc. a) For 100 ㎒ to 6 ㎓ and test separation distances ≤ 50 ㎜, the 1-g and 10-g SAR test exclusion thresholds are determined by the following: [(max. power of channel, including tune-up tolerance, ㎽) / (min. test separation distance, ㎜)] · [√f(㎓)] ≤ 3.0 for 1-g SAR, and ≤ 7.5 for 10-g extremity SAR,30 where ● f(㎓) is the RF channel transmit frequency in ㎓ ● Power and distance are rounded to the nearest ㎽ and mm before calculation ● The result is rounded to one decimal place for comparison ● The values 3.0 and 7.5 are referred to as numeric thresholds in step b) below The test exclusions are applicable only when the minimum test separation distance is ≤ 50 ㎜, and for transmission frequencies between 100 ㎒ and 6 ㎓. When the minimum test separation distance is < 5 ㎜, a distance of 5 ㎜ according to 4.1 f) is applied to determine SAR test exclusion. b) For 100 ㎒ to 6 ㎓ and test separation distances > 50 ㎜, the 1-g and 10-g SAR test exclusion thresholds are determined by the following (also illustrated in Appendix B): 1) {[Power allowed at numeric threshold for 50 ㎜ in step a)] + [(test separation distance – 50 ㎜)·(f(㎒)/150)]} ㎽, for 100 ㎒ to 1500 ㎒ 2) {[Power allowed at numeric threshold for 50 ㎜ in step a)] + [(test separation distance – 50 ㎜)·10]} ㎽, for > 1500 ㎒ and ≤ 6 ㎓ c) For frequencies below 100 ㎒, the following may be considered for SAR test exclusion (also illustrated This test report shall not be reproduced, except in full, without the written approval in Appendix C): 1) For test separation distances > 50 ㎜ and < 200 ㎜, the power threshold at the corresponding test separation distance at 100 ㎒ in step b) is multiplied by [1 + log(100/f(㎒))] 2) For test separation distances ≤ 50 ㎜, the power threshold determined by the equation in c) 1) for 50 ㎜ and 100 ㎒ is multiplied by ½ 3) SAR measurement procedures are not established below 100 ㎒. When SAR test exclusion cannot be applied, a KDB inquiry is required to determine SAR evaluation requirements for any SAR test results below 100 ㎒ to be acceptable. 2. Result 2-1. Calculation Result of RF Exposure Mode Test frequency [㎒] Max. tune-up Power [㏈m] Conducted output power [㎽/] Min. test separation distance [㎜] SAR test exclusion thresholds ≤ 7.5 for 10-g SAR BLE/1 Mbps 2 402 1.0 1.26 5.00 0.39 Note: 1. SAR test exclusion thresholds = [(max. power of channel, including tune-up tolerance, ㎽)/(min. test separation distance, ㎜)] · [√f(㎓)] = [(0.40)/(5)] · [√2.402] = 0.12 3. Target power and tolerance, Max tuneup power Mode Target power [㏈m] Tolerance [㏈] Max tuneup power [㏈m] Measured average Power [㏈m] Bluetooth LE_1 Mbps _2 402 ㎒ 0 ±1.0 1.0 -0.50 Bluetooth LE_1 Mbps _2 440 ㎒ 0 ±1.0 1.0 -0.29 Bluetooth LE_1 Mbps _2 480 ㎒ 0 ±1.0 1.0 -0.07 4. RF Exposure Compliance Issue Therefore, EUT is not required the SAR Evaluation.

Detail Specification: Page 1 of 10 Chip Antenna Mechanical Dimensions ±± W ±± T a ±± www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved 0.10 100% Tin Packing Style 0.063 Function No. Terminal Configuration 1.600.004 Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. 0.0040.031 0.016 0.010 0.80 1 2 FEED NC 0.25 max.0.40 0.004 0.10 0.10 max. P/N Suffix Part Number Explanation Evaluation Board 2450AT14A0100-EB1SMA & 2450AT14A0100-EB2SMA see pages 2&6 for details Bulk (loose) T & R Suffix = T or S Suffix = Te.g. 2450AT14A0100T (4,000pcs/reel) e.g. 2450AT14A0100SSuffix = S L mmIn e.g. 2450AT14A0100(T or S) Storage Temperature Operating Temperature Reel Quantity "High Frequency Ceramic Solutions" P/N 2450AT14A0100 Let us help you with the antenna design (free), optimization, and tuning (small fee may apply) 2/8/2018 2.4 GHz Mini Chip Antenna for 802.11, WiFi, WLAN, IoT with Small Area and GND size, ultra low profile 2450AT14A0100 48% -0.5 dBi typ. (XZ-Total) General Specifications Part Number Frequency (GHz) Avg. Rad Efficiency 1 Peak Gain 1 (dBi typ.) 2.4 - 2.48 Average Gain (dBi typ.)-2.0 dBi typ. (XZ-Total) 9.5 Typ. (6 min.) 50 Ω 2 Watts max. (CW) Return Loss (dB) Impedance Input Power 4000 -40 to +85°C -40 to +85°C Recommended Storage Conditions of unused product on T&R and period +5 to +35°C, Humidity 45~75%RH, 18 months max. L a W   T Top Side AEC-Q200 qualification available. 1 Measured on 2450AT14A0100-EB2SMA Contact our RF Engineers at: www.johansontechnology.com/ask-a-question for any questions you have, including tips or help on tuning the antenna www.johansontechnology.com/ask-a-question P/N 2450AT14A0100 Detail Specification: Page 2 of 10 www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved Mounting Considerations 1: Evaluation Board (small PCB) Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. "High Frequency Ceramic Solutions" 2/8/2018 2.4 GHz Mini Chip Antenna for 802.11, WiFi, WLAN, IoT with Small Area and GND size, ultra low profile GND 15mm 17mm 5mm No Ground 7mm 50W Feed Line 22mm To order a pre-tuned 50Ω EVB like the above with a female SMA connector click here: www.johansontechnology.com/request-a-sample Reference p/n: 2450AT14A0100-EB1SMA Would you like the layout file of the above? Having antenna tuning issues? Contact us by clicking on the link below (we're fast to respond!) . If you have any questions regarding the implementation of this antenna in your PCB, we'll be happy to guide you to maximize the antenna's performance. Contact our applications engineers at: www.johansontechnology.com/ask-a-question Detailed layout measurements, pad sizes, pattern geometry, etc. on the next page P/N 2450AT14A0100 Detail Specification: Page 3 of 10 Mount these devices with red mark facing up. www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved "High Frequency Ceramic Solutions" 2/8/2018 Mounting Considerations 1: Antenna Footprint Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. 2.4 GHz Mini Chip Antenna for 802.11, WiFi, WLAN, IoT with Small Area and GND size, ultra low profile 8.2pF 1.5nH 0.8mm 0.5mm 5.2mm 1.1mm 2.4mm Matching circuit ("pi" matching topology recommended) 0.85mm 0.65mm 2.0mm 0.5mm 0.8mm 1.43mm 0.55mm (Matching circuit and component values will be different, depending on PCB layout) Antenna Reference Layout Land Solder Resist P/N 2450AT14A0100 Detail Specification: Page 4 of 10 www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. "High Frequency Ceramic Solutions" 2/8/2018 Mounting Considerations 1: Typical Electrical Performance (T=25°C) 2.4 GHz Mini Chip Antenna for 802.11, WiFi, WLAN, IoT with Small Area and GND size, ultra low profile 2.2 2.4 2.6 2.8 2.0 3.0 -25 -20 -15 -10 -5 -30 0 freq, GHz dB(S(1,1)) Readout m1 Readout m2 Readout m3 m1 freq= dB(S(1,1))=-11.802 2.480GHz m2 freq= dB(S(1,1))=-7.237 2.400GHz m3 freq= dB(S(1,1))=-19.172 2.440GHz P/N 2450AT14A0100 Detail Specification: Page 5 of 10 www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved "High Frequency Ceramic Solutions" Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. Mounting Considerations 1: Typical EM Radiation Performance @ 2.44GHz (T=25°C) 2/8/2018 2.4 GHz Mini Chip Antenna for 802.11, WiFi, WLAN, IoT with Small Area and GND size, ultra low profile ) ) ) ) ) ) ) ) ) Y :Φ(Phi)=90 o X :Φ(Phi)=0 o Z : θ(Theta)=0 o XY-plane @2.44 GHz Total XZ-plane @2.44 GHz Total YZ-plane @2.44 GHz Total P/N 2450AT14A0100 Detail Specification: Page 6 of 10 www.johansontechnology.com 4001 Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FAX 805.389.1821 Ver. 1.3 2017 Johanson Technology, Inc. All Rights Reserved "High Frequency Ceramic Solutions" 2/8/2018 Mounting Considerations 2: Evaluation Board (larger PCB) Johanson Technology, Inc. reserves the right to make design changes without notice. All sales are subject to Johanson Technology, Inc. terms and conditions. Frequency (GHz)Radiated E…

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verify No.401034789746 Eurofins KCTL Co.,Ltd. 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea TEL: 82-31-285-0894 FAX: 82-505-299-8311 www.kctl.co.kr Report No.: KR23-SRF0024 Page (2) of (34) KCTL-TIR001-003/7 (220705) KP22-05729 REPORT REVISION HISTORY Date Revision Page No 2023-01-13 Originally issued - This report shall not be reproduced except in full, without the written approval of Eurofins KCTL Co.,Ltd. This document may be altered or revised by Eurofins KCTL Co.,Ltd. personnel only, and shall be noted in the revision section of the document. Any alteration of this document not carried out by Eurofins KCTL Co.,Ltd. will constitute fraud and shall nullify the document. This test report is a general report that does not use the KOLAS accreditation mark and is not related to KS Q ISO/IEC 17025 and KOLAS accreditation. General remarks for test reports Statement concerning the uncertainty of the measurement systems used for the tests (may be required by the product standard or client) Internal procedure used for type testing through which traceability of the measuring uncertainty has been established: Procedure number, issue date and title: Calculations leading to the reported values are on file with the testing laboratory that conducted the testing. Statement not required by the standard or client used for type testing Eurofins KCTL Co.,Ltd. 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea TEL: 82-31-285-0894 FAX: 82-505-299-8311 www.kctl.co.kr Report No.: KR23-SRF0024 Page (3) of (34) KCTL-TIR001-003/7 (220705) KP22-05729 CONTENTS 1.General information ......................................................................................................4 2.Device information ........................................................................................................4 2.1. Accessory information ............................................................................................4 2.2. Frequency/channel operations................................................................................5 2.3. RF power setting in TEST SW ................................................................................5 2.4. Duty Cycle Factor ...................................................................................................5 3.Antenna requirement ....................................................................................................6 4.Summary of tests ..........................................................................................................7 5.Measurement uncertainty .............................................................................................8 6.Measurement results explanation example ..................................................................9 7.Test results ................................................................................................................. 10 7.1. Maximum peak output power ................................................................................ 10 7.2. Peak Power Spectral Density ............................................................................... 13 7.3. 6 ㏈ Bandwidth(DTS Channel Bandwidth) .......................................................... 15 7.4. Spurious Emission, Band Edge and Restricted bands .......................................... 17 7.5. Conducted Spurious Emission .............................................................................. 30 7.6. AC Conducted emission ....................................................................................... 32 8.Measurement equipment ............................................................................................ 34 Eurofins KCTL Co.,Ltd. 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea TEL: 82-31-285-0894 FAX: 82-505-299-8311 www.kctl.co.kr Report No.: KR23-SRF0024 Page (4) of (34) KCTL-TIR001-003/7 (220705) KP22-05729 1.General information Client : Linkface Co., Ltd. Address : 501-ho, 11, Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea Manufacturer : Linkface Co., Ltd. Address : 501-ho, 11, Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea Laboratory : Eurofins KCTL Co.,Ltd. Address : 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea Accreditations : FCC Site Designation No: KR0040, FCC Site Registration No: 687132 VCCI Registration No. : R-20080, G-20078, C-20059, T-20056 CAB Identifier: KR0040 ISED Number: 8035A KOLAS No.: KT231 2.Device information Equipment under test : DearBuds SE Model : DBSE-22 Frequency range : 2 402 ㎒ ~ 2 480 ㎒ Modulation technique : GFSK Number of channels : 40 ch Power source : DC 3.6 V Antenna specification : PCB chip antenna Antenna gain : -0.5 ㏈i Software version : B1A1 Hardware version : 1234 Operation temperature : -10 °C ~ 50 °C 2.1. Accessory information Equipment Manufacturer Model Serial No. Power source N/A - - -- Eurofins KCTL Co.,Ltd. 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea TEL: 82-31-285-0894 FAX: 82-505-299-8311 www.kctl.co.kr Report No.: KR23-SRF0024 Page (5) of (34) KCTL-TIR001-003/7 (220705) KP22-05729 2.2. Frequency/channel operations This device contains the following capabilities: Bluetooth Low Energy Ch. Frequency (㎒) 00 2 402 . . . . 19 2 440 . . . . 39 2 480 Table 2.2.1. Bluetooth Low Energy 2.3. RF power setting in TEST SW Frequency(㎒) RF Power setting value 2 402 0 2 440 0 2 480 0 2.4. Duty Cycle Factor Test mode Period (ms) On time (ms) Duty cycle Duty Cycle Factor (dB) (Linear) (%) 1M Bits/s, 37 Packet 0.626 0.391 0.624 8 62.48 2.04 Notes. 1.DCF is not compensated to average result because duty cycle is 100% Eurofins KCTL Co.,Ltd. 65, Sinwon-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16677, Korea TEL: 82-31-285-0894 FAX: 82-505-299-8311 www.kctl.co.kr Report No.: KR23-SRF0024 Page (6) of (34) KCTL-TIR001-003/7 (220705) KP22-05729 3.Antenna requirement Requirement of FCC part section 15.203: An intentional r…

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This document shall not be reproduced, except in full, without the written approval Test setup photos - 9 ㎑ ~ 30 ㎒ - 30 ㎒ ~ 1 ㎓ This document shall not be reproduced, except in full, without the written approval - 1 ㎓~ 18 ㎓ - 18 ㎓ ~ 26.5 ㎓ This document shall not be reproduced, except in full, without the written approval - Conducted Emission