The Ultimate Choice of Pulse Oximeters: Long Range: Rechargeable via USB cable, 72 hours extra-long battery life. High Accuracy: More accurate and stable, record every second automatically with transmittance oximetry technology. Continuous Monitor: Tracks your blood oxygen saturation level, heart rate, and body movements for up to 9 whole nights. Real-time Check: Large screen displays every second readings. Free Report: Print & share two-second interval, high-resolution PDF/CVS format oximetry reports without additional fees.  Large Storage: Record and store long-term data trends on your phone, tablet, laptop, and desktop. Comfortable Design: The soft silicone material makes Checkme™ O2 comfortable to wear overnight.