Trijicon Night Sight Sets for Glock Pistols WHITE RINGS: Bright & Tough Night Sights feature a white ring around the glowing dots for daylight visibility TRITIUM-PHOSPHOR LAMP: Tritium-filled glass lamp provides superior illumination in no light or low light settings SAPPHIRE WINDOW: Each Trijicon tritium lamp is capped with a sapphire jewel which helps to evenly distribute the light from the tritium lamp as well as protect it from solvents and puncture PROTECTIVE ALUMINUM CYLINDERS: Contains and protects the tritium gas filled lamps from heavy recoil and harsh cleaning solvents Fits Glock Models: 17, 17L, 19, 22, 23, 24, 25, 26, 27, 28, 31, 32, 33, 34, 35, 37, 38 and 39. Housed in a metal body and cushioned within silicone rubber feature a unique shock-resistant design