Compact appearance, more convenient to carry. A button to wake up, even the elderly can also be used simply. Two 1.5V AAA batteries can be used continuously for more than 15 hours, more environmental protection and energy saving. Heart beats per minute while at rest tells a lot about your internal  health and fitness levels. It is a strong indicator of your risk for  heart problems. Your body requires a very precise balance of oxygen in the blood. For your body to perform optimally, blood oxygen levels should  be above 95%. Can be connected to the phone or pad via Bluetooth , and through  the APP data analysis and preservation.