Replacing the Light Seal
The device has a user-replaceable light seal. You should check the light seal for wear or damage. A damaged light seal can result in poor heart rate data or discomfort.
Use your finger to remove the existing light seal from the back of the device.
NOTE: Do not use a sharp object to remove the light seal.
Align the new light seal.
Use your finger to press the light seal into place.
There should be no gaps between the light seal and the back of the device.