Features One button operation with optical sensor technology for 10 second fast measurement. Clear OLED display with four directional viewing for convenient reading. Displays blood oxygen saturation and heart rate. Automatic power off after 8 seconds for energy saving. The on-screen numbers flash when preset alarm values are reached. Includes a lanyard for portability during family use or travel. Specification Color: Blue and White Material: ABS Display Type: OLED Display SpO2 Measurement Range: 70% - 99% SpO2 Accuracy: ± 2% at 80% - 99%, ± 3% at 70% - 79% SpO2 Resolution: ± 1% PR Measurement Range: 30 BPM - 240 BPM PR Accuracy: ± 1 BPM Alarm Function: Flashing numbers (SpO2 > 100, SpO2 < 90) (PR > 130, PR < 60) Battery: 2 x 1.5V AAA batteries (not included) Working Current: 2.5mA Working Conditions: 5℃ - 40℃, relative humidity 15% - 80%, 70kPa - 106kPa Product Size: 55 x 30 x 32mm / 2.2 x 1.3 x 1.2in Product Weight: 26g / 0.9oz Package Size: 8 x 6.7 x 4.7cm / 3.1 x 2.6 x 1.9in Package Weight: 43g / 1.5oz Package Contents: 1 x Finger Pulse Oximeter (Button color is random) 1 x Lanyard 1 x User Manual (English)