Trijicon Night Sight Set for Walther PPS 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: Walther PPS, PPX, and PPS M2 models Trijicon Bright and Tough Night Sights Fits the Walther PPS Tritium-filled glass lamp provides superior illumination in no light or low light conditions Green lamps are warranted for 12 years from the date of manufacture Professional installation recommended