Important Information Install the battery close to the high quality and unfavorable pole markings Oximeter Accuracy Test Why favor us 1【Accurate and Reliable Detection】 8 seconds to get measurement results within ± 2% 2【8s Fast Measurement】 essentially the most advanced MCU chip and sensor Only need 8 seconds to get readings 3【Saving Power Consumption】 Daily use-250times or maybe more; continuous size for twenty-four hours 4【One Button Operation with Four-Way Rotation】 One button control which makes measurement extra handy and simpler 5【Large and Clear TFT display】 Four Colors TFT and Backlight Display makes the result really easy to read 6【Compact and Portable】 42 gcomes with a removable lanyard is convenient to hold on its personal or within your backpack 7【Visual Alert When Measuring】 the alert function If SpO2 or pulse price studying is under or above the preset limit, the device will alert with flash on the screen routinely 8【 Built-in Silicone Protector】 Built-in silicone membrane reduces the stress of the oximeter at the finger when size What includes? 1 x Pulse Oximeter, 1x Outer Packing, 1x Lanyard, 1 x Blister box ,1x Instruction Manual, and 1x Certificate of Qualification How to Use? If you could turn on the device, please check if the batteries were inserted correctly