Description: Using this product can open smart door lock, one-card recharge, and lock important file, it is widely applied and multi-function, which is convenient and easy to use. What a ring can be a perfect accessory to match your clothes and outfit with its smooth surface and exquisite workmanship, which is fashionable and trendy to use. Made of stainless material, this product is durable and long lasting. There are eight sizes that you can choose from. It can apply for Android NFC phone. You can download NFC Tools PRO 4.0 Chinese version or English version software for easy operations. Item Name: NFC Chip Ring Material: Stainless Steel Chip: for Ntag213 Features: Sensitive, Fashionable, Electronic Product Size Details: Size: US 6, Circumference: 5cm/2", Diameter: 1.6cm/0.6" (Approx.) Size: US 7, Circumference: 5.33cm/2.1", Diameter: 1.7cm/0.7" (Approx.) Size: US 8, Circumference: 5.65cm/2.2", Diameter: 1.8cm/0.7" (Approx.) Size: US 9, Circumference: 5.96cm/2.3", Diameter: 1.9cm/0.7" (Approx.) Size: US 10, Circumference: 6.28cm/2.5", Diameter: 2cm/0.8" (Approx.) Size: US 11, Circumference: 6.59cm/2.6", Diameter: 2.1cm/0.8" (Approx.) Size: US 12, Circumference: 6.9cm/2.7", Diameter: 2.2cm/0.9" (Approx.) Size: US 13, Circumference: 7.22cm/2.8", Diameter: 2.3cm/0.9" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x NFC Chip Ring