The Beretta Night Sight Set features tritium gas-filled lamps with a sapphire front lens which focuses light and is impervious to solvents. The sapphire lens-enhanced tritium vial, is on of the brightest in the industry. THe gas-filled lamps are silicone cushioned to take years of use and come with a full warranty. FeaturesPrecision Machined Metal Body Lamps glow green in the dark and have white outlines for the daylightImpervious to solvents and punctureScrews included for assembly