Measures Oxygen Saturation (SpO2), Pulse Rate (PR), Perfusion Index (PI) & Pulse bar Simple to operate and convenient to carry Dual colour OLED display screen Easy to read display Quick, Compact & Portable Patented directional change display - Display will switch orientation making it easy to read, helps reduce arterial blood constriction improving accuracy Simple one button measurement Automatic power-off to save battery life Intended for use on adults, adolescent and children. Powered by 2 x AAA batteries (included)