It won't work without power - Lasermax Batteries Silver Oxide Fits Glock, XD

You gotta have batteries to work this laser sight. All of us like to have a back up battery pack so we can test the sight and practice using it.
Only negative is the price, but still worth it.
Pros: simple and compact
Cons: Price a little high

This review was written in the old system and had content requirements that are different than reviews written today.