PIRG is equipped with a green laser, which is brighter than any red laser and easier to find even when its not completely dark. Pistol sights are usually calibrated from time to time. . * * Specifications * Beam intensity/wavelength: <5 mW peak, 532 nm, Class IIIA * Laser beam divergence: 1.2 mrad * Spot size: Approximately 0.1 inches in diameter at 50 feet * Range: Up to 100 yards in daylight, up to 2 miles at night * User-adjustable: Yes, full windage and elevation * Construction: high-strength Zytel polymer * Power source: 3.7 V 60 mAh rechargeable battery with USB charger kit (included) * Battery life: 2~3 plus hours laser (constant), charging time: 2 hours * Installation: Loosen the screw, slides onto tactical rail, then tighten the screw * Ambidextrous activation/deactivation * Dimensions: Dimension: LxWxH: 1.61" x 0.83" x 1.22"; weight: 0.5 oz * Weight: 0.5 ounces * Included accessories: an Allen wrench, a set of USB charging kit, user's manual Troubleshooting * If the laser beam is dim, please recharge the unit * If the unit runtime is too short, the unit may not be well charged. Please charge it overnight * If the runitme is still short after overnight charging, it may be caused by a bad charger. Please try to use iPhone charger to charge it overnight * If the laser beam is off target, please tune the laser with included Allen wrench * If the unit is not properly mounted on pistol, please replace the polymer mount plate with metal mount plate included