How do I replace the batteries?

Rotate the alarm counterclockwise and off its mounting bracket. On the back is the battery cover, remove this and replace the batteries. Remember to tilt the red safety pin under the batteries when you put them back in.
Test the alarm by pressing the button on the alarm once. It should confirm with a red flash and a “2-tone” beep.
Mount it again and check that it is properly attached.

Tip: the batteries are of the CR123 type and each alarm needs 3 pcs. It will not work with rechargeable batteries.