Gently used I upgraded to a Samsung smart watch and no longer need this one. This is a model M2 TANK smart watch. It retails at Amazon for $100 comes with magnetic usb charger. The M2 uses a military grade 100% pure cobalt battery, with a capacity up to 380mAh which is 2-3 times the capacity of ordinary smart watches; which ensures a standby time of 45-60 days and daily use of 10-15 days. Made of Special composite materials and metal shell it pass twelve military standard tests including damp heat, shock test, low temperature test high temperature test, vibration test, rain test, salt spray test, low pressure test, fungus test, contamination by fluids test, sand and dust test, solar radiation. And it’s waterproof! featuring waterproof speakers and MIC, it’s waterproof up to 50 meters water pressure. Giving this watch a M2 rating that has got through the demanding IP69K rating test, so that you can wear it during all day-to-day water sports and activities such as swimming, diving, surfing and more. It also has one of the most extensive sports / health algorithms of any watch on the market; with 70 sports modes, including hiking, skiing, swimming and other indoor and outdoor workouts. And it Harnesses the leading PPG BioTracker optical sensor which helps you maintain your health by monitoring heart rate, sleep and blood oxygen on-demand and allows you to Track and assesses your sleep in various dimensions