Specifications Hign-concerned Chemical:None Model Number:CUID+T5577 Ring Origin:Mainland China Certification:CE color:black Product name:125Khz/13.56Mhz Ring Special Features:Waterproof / Weatherproof 125Khz 13.56Mhz Frequency Black Ring Smart Chip Dual T5577+CUID Rewritable Tag ID IC Clone Badge Token Copy Duplicator Write Caution: The ID (125KHZ) Chip Is The T5577 Chip, The Card Number Is Empty, It Needs To Be Read After Writing. The IC Chip (13.56Mhz) Is A CUID Chip.(Please make sure the machine supports writing to CUID card) Please Use A Professional Duplicator When Copying, If You Need, Please Contact Customer Service. Specific measurement methods: Please use a thin line or paper strip to measure the circumference of the finger wearing the ring, and select the number corresponding to the size chart above. 1. Use a thin, non-elastic rope. 2. Make a circle around the place where you wear the ring and tighten the measuring line. 3. Use a ruler to measure the length of the rope. Precautions: 1. Use thin paper strips or ropes to measure the position of your fingers. Do not measure the finger joints. Make a mark where the paper strips or ropes overlap. 2. During the test, be sure to tighten the paper strip or rope, measure multiple times and take the average, and control the error within 1MM to avoid abnormal differences. 3.Because some customers may not measure accurately, we usually send them the size they choose, but we may also send a larger size to avoid being unable to wear it! About Size: No. 6: circumference 53MM, diameter 16.5MM No. 7: circumference 56MM, diameter 17.3MM No. 8: circumference 59MM, diameter 18.2MM No. 9: circumference 62MM, diameter 18.9MM No. 10: circumference 65MM, diameter 19.8MM In terms of appearance, it basically matches the picture. If there are slight deviations, please refer to the actual product. Packaging: smart ring The ring size error is less than or equal to 1MM, you can choose the size you need! Please refer to the actual product! About writing cards: The ID writing area is the inner diameter marking area, and the IC is in the middle position corresponding to the marking (that is, the other side of the circle diameter, please try) Please see the picture below.