Trijicon, Bright & Tough, Sight, Suppressor Set, Fits Glock 20,21,29,30 and 41 (including S and SF variants), Black Front/Black Rear with Green LampsTRIJICON NS SUP SET FOR GLK 20 B B: Trijicon Bright & Tough(TM) Night Sights are three dot iron sights that increase night fire shooting accuracy by as much as five times over conventional sights. Equally impressive, they do so with the same speed as instinctive shooting and without the need for batteries Features : Tritium Phosphor lamp Sapphire window White rings Silicone rubber cushion Protective aluminum cylinders Suppressor sights Back up iron