Fits FN509 - Trijicon Bright & Tough™ 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. Housed in a metal body and cushioned within silicone rubber Bright & Tough Night Sights feature a unique shock-resistant design. Each lamp is capped with a sapphire jewel to help evenly distribute the light while protecting the lamp from solvents and puncture. Contained within aluminum cylinders for additional protection the lamps are mounted on silicone rubber cushions to withstand shock and heavy recoil. Green lamps are warranted for 12 years from the date of manufacture.