1.Lever the battery cover open by using the clip on the strap. Picture D1.
2.Remove the old battery from the battery cover with a suitable sized small rigid stick or bar, such as a toothpick. A
3.Insert a new battery (CR 2025) inside the cover with the negative
4.Align the ledge on the battery cover with the slot on the connector and press the battery cover back into place. You should hear a snap. Picture D4.
When changing the battery, make sure the sealing ring is not damaged, in which case you should replace it with a new one to ensure the water resistance of the connector. For video tutorials on how to change the batteries, go to www.polar.com/en/polar_community/videos.
You can purchase the sealing ring/battery kits at