Keyfobs: Unscrew the back and pop open, replace with two or one watch batteries depending on the type of key fob. Maxell CR 2032; Duracell DL 2032 or Sener
CR2032 – only use lithium batteries
Door and window sensors: Look for tabs on the sensors and depress. The top will open. Replace batteries.
Smoke and Fire Detectors: Align tab with arrow and turn counter-clock wise to remove cover and replace batteries. To close, turn clock wise and make sure it clicks.