Lasermax guide rod laser meets or exceeds both mil-spec and homeland security durability test standards (drop tests, blowing sand, temperature and humidity extremes, salt water, fog, deep water immersion, 20,000+ rounds live fire).It has an on/off switch on the takedown lever.No gunsmithing required to install.These pulsating red lasers install as the internal guide rod as close to the bore as possible for a close point of aim/point of impact relationship.Factory aligned for center-of-mass accuracy at 20 yards, they never need realignment, even after changing batteries.The ambidextrous on/off switch is located in the custom take-down lever for deliberate activation.Power Switch: On/OffWavelength: 520nMDot Size: .75" @ 25 ydsPower: 5mWRange: 20 ydsWeight: 76 ozBattery: 393Laser Color: GreenFirearm Fit: Glock 17 Gen5Adjustments: NoFinish: BlackMount Type: Under Barrel