AGPtek YM101 is a portable device used to measure blood oxygen levels and pulse rate. It offers customizable settings for brightness, alarms, and software version check. Proper usage involves installing batteries, inserting a finger, and pressing the button to activate the device. For accurate readings, avoid testing with painted fingers or toenails, under bright light, or while moving. Normal range for healthy individuals is SpO2 >94 and 60 < PR < 120.