Be prepared to play returnicake. - Streamlight TLR RM 2 Laser Rail Mounted Tactical Lighting System

If you get a good unit, these are pretty nice lights for the money, but so far anything from Streamlight that includes laser alignment has a very high chance of being defective right out of the box.

You can play returnicake with optics planet, and hope that within your returnable limit (I think it allows one exchange), you get a fully functional unit, or you can send the unit into warranty repair at Streamlight, which is the cost of shipping each trip, and they mostly tend to get them fixed the first time, but not always.

I don't know a better alternative for the money, overall, so I bake this possible hassle factor into the pricing. You save a little on factory assembly QC, you may or may not pay it back and a bit more in shipping cost and your time.