Viridian green laser for glock 17 - Viridian Sight for Glocks with Rails

I received my Viridian Green Laser two days ago for my Glock 17. I took it out to the range today to get it zeroed in to the gun. I fired about 30 rounds and was enjoying the ease of shooting with the laser sight. Then it just stop working. Could not turn it on or off. At first I thought it was the battery and replaced it with a new one. No deal. Still could not get it to turn on. I removed sight from the gun. I found if I pointed the sight toward the ceiling the laser would come on but if I pointed it level the laser went off. Go figure. For the cost of this laser sight I would have thought that it would have been built better. Since it sits on the end of a gun that produces high G shock every time it fires. It looks like it can't operate in that environment.
Pros: Easy to install
Cons: Must be reliable

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