Trijicon GL104Y-600545 HD Night Sights for Glock 21 provide a high-visibility sight picture for precise target acquisition in low-light conditions. Tritium illumination and a yellow front outline support rapid alignment in darkness and clear visibility by day.Designed with input from law enforcement and professional shooters, these robust sights deliver dependable performance through changing light conditions, heavy recoil, and exposure to harsh cleaning solvents.Visible tritium sight picture in low or no lightBright yellow front outline improves daylight dot visibilityDurable construction resists recoil and cleaning solventsEvenly distributed illumination supports consistent alignmentEquip your Glock 21 with Trijicon HD night sights for reliable, precise aiming in demanding conditions.