Fingertip Pulse Oximeter Heart Rate Monitor Spo2 Blood Oxygen Saturation Device Item Type: Finger Pulse Oximeter Material: ABS Color: Black and WhitePower Supply Mode: 2 x AAA batteries (Not included) Instructions for Use:  1. Insert two 1.5V batteries(not included) according to the positive and negative signs in the battery slot and close the battery cover. 2.Pinch open the clip of the finger clip pulse oximeter, insert your finger into the rubber channel (the finger should be fully extended), then release the clip, and click the switch button on the front panel; 3.Do not shake your fingers during use, and it is best not to move the human body in order to read accurate data; 4. After booting, the interface direction switch defaults to the button mode, short press (less than 2 seconds) the button, can realize the fixed order switch of 4 directions. 5. Automatically shut down after 8 seconds without finger induction.