Features: 1. Through the NFC radio frequency communication technology and mobile phone connection to the mobile phone function operation and sharing of data. 2. No charge / depth waterproof, built-in ultra-sensitive NFC chip, no electricity to work, easy to wear. 3. Multi-functional NFC smart ring, the main function is to store and exchange information, as well as mobile content and encryption unlock. 4. Lock / unlock the program, select the application you want to lock / unlock, write the smart ring, only the touch the phone to start the application, to protect privacy. 5. Beautiful appearance, easy to use. Specification: Material: Metal Size: about 4*5*0.5cm/1.57*1.97*0.2in Product Name: NFC Multi-function Smart Ring Size: 6/7/8/9/10/11/12/13 inch Package List: 1 * Smart Ring 1 * Instruction Manual Instructions for use: 1. First, check if your smartphone has NFC function. It can usually be found in the system settings. If no relevant options are found, contact with the manufacturer post-sale support, or search on if the smartphone model has NFC function and confirm its NFC area. 2. If your smartphone has NFC function, turn on the NFC switch, search your app for the software which apply NFC, download and install them. 3. Start the NFC APP, perform actions according to the instructions. 4. Since NFC is a near field communication technology, make sure to place the top side of the chip right close to the NFC area when reading any data to avoid the failure in reading and writing.No charge / depth waterproof, built-in ultra-sensitive NFC chip, no electricity to work, easy to wear. Lock / unlock the program, select the application you want to lock / unlock, write the smart ring, only the touch the phone to start the application, to protect privacy. Through the NFC radio frequency communication technology and mobile phone connection to the mobile phone function operation and sharing of data. Multi-functional NFC smart ring, the main function is to store and exchange information, as well as mobile content and encryption unlock. Beautiful appearance, easy to use. Beautiful appearance, easy to use.Manufacturer: Ranvo. Date First Available: August 26, 2021. Best Sellers Rank: #158,568 in Electronics. Customer Reviews: 3.0 out of 5 stars 2 ratings 3.0 out of 5 stars. : B09DPV2CG7. Item Weight: 0.238 ounces. Product Dimensions: 1.57 x 1.97 x 0.2 inches.