I have two of these 1" light mounts. They fit rails tightly and do not loosen. They are adjustable to hold various brands of lights around 1" diameter. The only durability question is the polymer strap that actually holds the light. I think if you had it adjusted too tightly and tried to cam it shut, you could break it. Long-term durability might be a issue, but I am not in a combat situation, just coyote/pig hunting, pest control, home defense.
Pros: Good Value, Simple, Lightweight, Highly Versatile
Cons: Could break the plastic/polymer strap
This review was written in the old system and had content requirements that are different than reviews written today.