Tracks distance traveled, calories burned, steps taken, various activities and automatic monitoring of length and Quality of sleep. Crafted from aircraft grade aluminum, misfit ray Features a minimalist, modular design, and is water resistant to 50 meters. Replaceable button Cell batteries last up to 6 months. With vibration alerts, movement reminders, and multi-color LED display, ray introduces new ways to interact and motivate you to meet your Health and fitness goals. Misfit ray offers Smart notifications so you'll never Miss an important call again. Features hidden 8-mm spring bars that allows ray to be worn with almost any standard accessory, including watch bands, bracelets, or necklaces.