TRU-GLO MUZZLE•BRITE XTREME UNIVERSAL Ghost ring and notched rear sight NOW AVAILABLE WITH INTERCHANGEABLE REAR SIGHTS! Universal mounting system for in-line muzzleloaders. CNC machined. Full windage & elevation adjustment. Mounting hardware included. Front diameter is .040"; rear diameter is .029". Universal mounting system for in-line muzzleloaders. CNC-machined. Full windage and elevation adjustment. Mounting hardware included. Front diameter is .040"; rear diameter is .029". Endorsed by the Rocky Mountain Elk Foundation.