Waterproof: Made with an NFC chip, the waterproof and durable ring does not require charging! Smart ring: Get a multifunctional Bluetooth smart ring. Sizes: Choose from six sizes (see Full Details for measurements). Essentials: Easily access your payments, schedule, send messages and pictures and even unlock your front door using the smart ring. Perfect for keeping your essentials safe and with you at all times! Bluetooth: Compatible with Android, iOS and Windows, connecting seamlessly through Bluetooth. Privacy: If your ring is lost, simply block access through your smartphone to maintain the safety of your data. Multi-Functional Bluetooth Smart Ring | Living Social