1. Accurate and Reliable: This tester can accurately determine your SpO2 (blood oxygen saturation levels), pulse rate and pulse strength in 8 seconds and display it conveniently on a 1.5 inch large digital LED display. Ship from China, 6-8 days delivery to USA 2.Easy to Use: Taking a reading is easy, just clip it on to your finger and turn it on at the press of a button. NOTE: Sports and aviation use only, non-medical use. 3. Practical in Use: The product requires only two AAA BATTERIES that will allow you to use the pulse monitor right out of the box, suitable for all people above 4 years old.