These moon clips are designed to work in the Ruger Super GP100 8 Shot, chambered in 9 MM.
These are sold as THIN moon clips.
The normal moon clip thickness is 0.035" and these are 0.032" thick.
The thickness of the moon clip is thinner, giving rounds more room to move around in the chamber.
Great for big matches, high round counts and easier than reaming the chambers.