Keep Relaxed measuring, down quietly for a moment,Palms up, put the wrist band parallel to the heart Palms up, keep the pipe and the arteries parallelled, Wrap the wrist band around your arm tightly in the opposite direction, paste Place one finger into it is the most appropriate, Keep the wrist band parallelled to the heart, palms up Press the on/off button, keep relaxed and measuring. Material: ABS colour: Black-gray Package Contents: 1 x 1 x arm band 1 x storage bag Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.