If you would like to track your oxygen level and heart rate over time, and obtain a full picture about how your body performs during certain period, this is your choice. Not only does it display your blood oxygen in real time, but it also records the data for up to 40 continuous hours. Both spot and continuous monitoring are perfectly fulfilled in this device. What's more, it won't miss a single second of reading ensuring all your important data are captured. Notes: Intended for sports & aviation use only, not for medical or diagnostic purpose.