This is a Fusion Custom, Mil Spec style rear Night Sight. Green Trijicon tritium with White outline, great for all light conditions. Springfield 1911A1 series Mil spec style dovetail, 50 Degree x .330 dovetail. Dovetail also has Locking screw & Wrench to retain sight in dovetail. This sight set comes with Green Trijicon trtitium with white outline Front, mil spec/ 80 series .080 Wide staking post. This is one of the best rear sights for quick target acquisition in all lighting conditions. Standard Mil Spec Springfield 1911A1 series dovetail base, which is the most common rear mil spec style sight dovetail. CNC Machined from steel bar-stock with black oxide finish…. MADE in the USA….. Trijicon Tritium.