Viridian GLK Green Laser Sight Built for Glock's with Rails with Holster Features highly visible green laser for visibility up to 100 yards in broad day light and up to 2 miles at night. Fully ambidextrous featuring SMARTLASER technology which offers 4 different operating modes. Up to 7 hours of runtime on 1 CR2 3 Volt Lithium Battery (included). Includes custom fit Kydex holster to accommodate your Viridian. Weighs only 2.7 ounces including battery--constructed of high strength Zytel polymer.