 Welcome! The following video will demonstrate how to insert and replace the batteries for a 2GIG Thin-Door Window Contact. Begin by pushing down on the clip at the top of the sensor to unlock the sensor's backplate. Then you'll want to gently separate the sensor from the backplate. Place a small flathead screwdriver in the slot between the metal clip and the battery, and then use the screwdriver to pop out each battery. Dispose and or recycle the used batteries in accordance with the hazardous waste recovery and recycling regulations for your location. Insert the replacement batteries into the battery compartments. You'll want to make sure the plus sign of both batteries is facing up and the minus side is facing down. Warning! Failure to follow these warnings and instructions can lead to heat generation, rupture, leakage, explosion, fire, or other injury or damage. Do not insert the battery into the compartment in the wrong direction. Always replace the battery with the same or equivalent type. Never recharge or disassemble the battery. Never place the battery in fire or water. Always keep batteries away from small children. If batteries are swallowed, promptly see a doctor. Finally, reattach the sensor to its backplate. The two gig-thin-door window contact batteries have now been replaced.