Battery Tutorial: Glass Break (2GIG GB1)
"You will need two CR123A batteries to change the battery in your glass break detector.
Before changing the batteries, make sure that your system is disarmed and note that you may here some beeping from the panel when you open the detector.
Go to your glass break detector and twist the top to remove it from the base.
Remove the old batteries and replace it with the new CR123A batteries.
Twist the detector back onto the base and make sure that it snaps into place with no gaps.
Remember to safely dispose of the old batteries.
For more information and tutorials, please visit support.vivint.com"