I gave it a two after the screw fell out. I emailed LaserLyte about the problem. I got an email (same day) from LaserLyte customer service. Nice person asked for mailing address to send me two new screws and some locktight type sealer. The person provided tips on how to adjust the laser that would reduce the possibility of a screw coming lose along with some other tips. At least they do have a good customer service dept. It worked for me.

I purchased this laser for my Taurus PT 917c 9mm. At first I was very happy with it. I adjusted it to the gun sights and it was cool. Then I went to the range and actually fired a few rounds. (outside range and the laser was useless in the daylight) (normal) Went inside to "fine tune" the laser sight and to my suprize it was several FEET off. The windage adjustment screw had fallen out in less than 50 rounds. It is worthless. I am trying to find a replacement screw and maybe I can set it and fingernail polish it in place. I am thinking blood red. Slide switch is not easy to turn on and off. That was close to $100 down the drain.

takes 5 minutes to put on and perfect size for a PS90 TR.