Fingertip Pulse Oximeter LED Dispaly Blood Oxygen Saturation Heart Rate Monitor with Strap Item Type: Fingertip Pulse OximeterMaterial: ABSColor: As Picture ShownWeight: Approx. 43.0g/1.5ozPower Supply Mode: 2pcs AAA Batteries (not Included) Instructions: 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 finger clip pulse oximeter clip, insert your finger into the rubber channel (the finger should be full insert), 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 turn on, the interface direction switching defaults to the button mode. Short press (less than 2 seconds) the button to achieve a fixed order switch in 4 directions 5. Automatically shut down after 8 seconds without finger induction.