I use these for IDPA to hold 17 round Glock mags with 10 rounds in them (per IDPA rules). They have never failed to work. Mags stay put, come out easy, and go back in easy. They stay put on the belt.
Occasionally I carry a spare Glock 26 mag in them and it has never fallen out.
I have several of these bought at different times and they all have a slightly different texture/shade. They are all black and all dimpled. This in no way effects the function. I will probably buy more as my kids start to shoot and need them.
Pros: Small, holds mag very well
Cons: none
This review was written in the old system and had content requirements that are different than reviews written today.