Answer to: Polar F11 Heart Rate Monitor battery replacement instructions?I just changed this battery 5 minutes ago. Once you remove the 4 screws on the back, lift the cover off. You'll see the battery facing you. Simply insert a small screwdriver in one of the holes at the rim of the battery and pry the battery out. To insert the battery, push it in (you may need to insert it slightly from the side). Be sure that the positive (+) side is facing you. Then put the cover back on and it's done. Good luck!