Feature Convenience 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 saving. Resting Heart Rate 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. Blood Oxygen Level 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%. Specification Operation system / SpO2 Detection scope: 35%-100% Accuracy: ±2% 80%-100% ±3% 70%-79% Pulse Rate Rage：25-250BPM Accuracy：±2BPM Resolution:1BPM Bluetooth / Battery Type Two 1.5V AAA alkaline batteries Service life Over 10000 times Display OLED Working voltage D.C.2.2 V~D.C.3.4V Operation environment Temperature: 5℃ - 40℃ Relative humidity: 15% - 80% Atmospheric pressure: 86Kpa - 106Kpa Size 58 (H) × 34 (W) × 30(D)mm Weight 50g Include batteries Delivery time Mass production: about 15 days (2000pieces)OEM: about 25 days