Features Real IP68 5ATM Waterproof Real IP68 5ATM depth waterproof using military grade materials and craftsmanship ingenuity The internal body uses the self circulation exhaust function so that the internal pressure of the machine is always maintained at one atmosphere to ensure the normal operation of the movement easily adapting to various environments High aluminum alloy frame face ring More skin friendly no sweat absorption reaction better protection of consumer skin no allergic reaction than zinc alloy aluminum alloy more corrosion resistance oxidation resistance high stability high aluminum alloy is environmentally friendly steel Stable BT CallConnecting Mille using the RTL8763EWE chip which is single core and dual mode It only need to connect to the phone one time and you can use BT calling and play the music easy to use Health Monitor Accurately record your heart rate blood pressure blood oxygen and sleep data helping you adjust yourself for a healthier life style Fitness Activity Tracker The activity tracker supports motion modes with comprehensive recording of exercise data Let you exercise more scientifically Smart Reminder After connected to the phone it will provide synchronous display of message call or social APP to remind you of important information Long Lasting Battery Life Tank M1 uses the industry s largest 600mAh polymer battery with circuit protection IC Stable battery curve long service life can last 75 days standby