All GONE Large diameter head is easy to hit in dark and stressful situations, even while wearing gloves. Extends an extra .100" to give positive magazine release without shifting your grip. The grooved contact surface offers competition or tactical users a secure, non-slip purchase. O-ring cushion prevents receiver wear and scratching. SPECS: Aluminum, Mil-Spec, 8625, Type III, Class Two, hard anodized, black, matte. Head - .625" (15.9mm) diameter. Photo of two mag releases with one stock release. I have a few extra, these are normally $20 retail $18 shipped conus.