This rail adapter is actually made by GG&G, but tends to be sold by a number of laser/light manufacturers under their own name (which isn't a big deal).
It's likely the only QUALITY rail adapter for the USP on the market right now.
I use mine with a laser/light combo and it does indeed hold it's zero very well.
Pros: Solid, Holds Zero
Cons: Little pricy for what it is
This review was written in the old system and had content requirements that are different than reviews written today.