ACCURATE and RELIABLE - the new version consistently beats other pulse oximeters in terms of accuracy and reliability during clinical tests. Only 8 seconds, it shows your measured SpO2 and Pulse Rate(PR) and pulse strength on a high-quality OLED display (with six multi-directional display choices). NEW ACCLAIMED FEATURES - Perfusion Index (PI) that will improve the reliability of the readings dramatically. The PI conveniently informs you of the strength of your pulse. The sleep monitoring function can keep the data record for 8 hours and it will start analysis after monitoring for more than 2 hours. SPORTS ENTHUSIASTS - Suitable for mountain climbers, skiers, bikers, aviators, or anyone interested in measuring their SpO2 and pulse rate on the move. NEW SOFTWARE FEATURES - 1) Auditory alarm to warn you when your SpO2 and Pulse Rate are beyond set limits. 2) Auditory Beep for every detected pulse. Long battery life, it could continuously work for 20 hours.