Interchangeable Pin Ring is truly fast and easy customization of your scope Swap out Ring Pins to change color or diameter depending upon the situation Rotate the Ring Pin to one of four keyed indexing slots at 12 O'clock, 3 O'clock, 6 O'clock, and 9 O'clock within the Scope Housing Fiber wrap provides protection and amazing light collection for Axcel's brightest Fiber Pin AXCEL® AVX Ring Pin For AVX-31 (31mm) or AVX-41 (41mm) Scopes Patented technology for quick interchangeability of ring pins. Choose: .010" or .019" Fiber in Green, Red, Yellow, or Blue