This is a Tri-Cam 4-piece set. I'm selling it because I no longer use it. They're still in good condition. Quoting from the product website: -------------------- This is a protection device that utilizes the camming effect, representing a classic piece of gear. It can be effective in frozen cracks or cracks filled with mud, where cams may not work. The larger sizes are lighter and stronger compared to cams of the same size. The #0.125~2.0 sizes have rigid slings for easier handling.