This light may work on a different manufacture of pistol, but it isn't right for the H&K usp compact. Called customer service at Streamlight asked if it needed something else to fit properly. They sent a key kit that had nothing to do with the this pistol and their light. Guess they don't know either.
Pros: Bright light focas is good
Cons: doesn't fit right.
This review was written in the old system and had content requirements that are different than reviews written today.