This is a Fusion Custom, Mil Spec style rear fiber optic sight. Green Florescent Fiber optic sight with standard Colt, 70, 80, 90 series, 50 Degree x .330 dovetail. Dovetail also has Locking screw & Wrench to retain sight in dovetail. This sight set comes with Green Front, mil spec/70 series .055 NARROW staking post. This is one of the best rear sights for quick target acquisition. Very bright!! Standard Mil Spec Colt 70, 80, 90 series dovetail base, which is the most common rear mil spec style sight dovetail. Used by many manufactures such as RIA, Colt, SAM, ...etc.1911 Colt Mil spec style pistols & Clones. .. CNC Machined from steel bar-stock with black oxide finish…. MADE in the USA….. Used standard 1.5mm or .062” Fiber rod, Rod supplied with sight.