2AK8Q-TKSD001TSpeaker Doorbell

Shenzhen Unichain Technology Co., Ltd 2023.09.05 Eurofins Electrical and Electronic Testing NA, Inc. 914 W. Patapsco Avenue Baltimore, MD 21230 USA RE: LETTER OF AGENT AUTHORIZATION To Whom It May Concern: We, the undersigned, hereby authorize Shenzhen BCTC Testing 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, Client’s signature: Client’s name / title : Zhiying Lan / Manager Contact information / address: 201, 111-3, Huangjinshan District, Bantian Community, Bantian Street, Longgang District, Shenzhen, China

Shenzhen Unichain Technology Co., Ltd 2023.09.05 Eurofins Electrical and Electronic Testing NA, Inc. 914 W. Patapsco Avenue Baltimore, MD 21230 USA RE: CONFIDENTIALITY REQUEST FOR EUT NAME: Speaker Doorbell Trademark: TECKNET/TeckNet MODEL: TK-SD001, TK-WD007 FCC ID: 2AK8Q-TKSD001T 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 - Block Diagram - Schematics - Operational Description required to be submitted with this application be permanently withheld from public review. The above materials contain trade secrets and proprietary information not customarily released to the public. The public disclosure of these materials may be harmful to the applicant and provide unjustified benefits to its competitors. Please contact me if there is any information you may need. Sincerely, Client’s signature: Client’s name / title : Zhiying Lan / Manager Contact information / address: 201, 111-3, Huangjinshan District, Bantian Community, Bantian Street, Longgang District, Shenzhen, China

Shenzhen Unichain Technology Co., Ltd Model Difference 2023/09/05 EUT NAME: Speaker Doorbell Trademark: TECKNET/TeckNet MODEL: TK-SD001, TK-WD007 All the model are the same circuit and RF module, except model names and appearance of the color. Regards Sincerely Client’s signature: Client’s name / title : Zhiying Lan / Manager Contact information / address: 201, 111-3, Huangjinshan District, Bantian Community, Bantian Street, Longgang District, Shenzhen, China

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FCC ID: 2AK8Q-TKSD001T Portable device According to §15.247(e)(i) and §1.1307(b)(1), systems operating under the provisions of this section shall be operated in a manner that ensures that the public is not exposed to radio frequency energy level in excess of the Commission’s guidelines. According to KDB447498 D01 General RF Exposure Guidance V06 The 1-g SAR and 10-g SAR test exclusion thresholds for 100 MHz to 6 GHz at test separation distances ≤ 50 mm are determined by: [(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 When the minimum test separation distance is < 5 mm, a distance of 5 mm is applied to determine SAR test exclusion. 433M Modulation Frequency MHz Output Power (dBuV/m) Output Power (dBm) ASK 433.92 86.72 -13.18 Below 1GHz: dBm=dBuV/m-95.2-4.7 Modulation Channel Freq. (GHz) Output Power (dBm) Output Power (mW) Tune-up power (dBm) Max tune-up power (dBm) Max tune-up power (mW) Distanc e (mm) Result calculation SAR Exclusion threshold SAR test exclusion ASK 0.434 -13.18 0.048084 -13±1 -12.00 0.063096 <5 0.008313 3.00 YES Conclusion: For the max result : 0.008313＜3, the SAR testing is not required.

珠海市奕凯五金制品有限公司 Zhuhai Yikai Hardware Products Co., LTD page 1 珠海市奕凯五金制品有限公司 Zhuhai Yikai Hardware Products Co., LTD 传真号码：0760-86380992 1EZX150051H 1、Antenna Dimensions (unit:mm) GBT-433-2.5DJ01 433MHZ 0.5*4.5MM 20T长度13.5mm 珠海市奕凯五金制品有限公司 Zhuhai Yikai Hardware Products Co., LTD 珠海市奕凯五金制品有限公司 Zhuhai Yikai Hardware Products Co., LTD 传真号码：0760-86380992 2、Antenna Picture page 2

Radiated Measurement Photos