Callfire@whole Kits Laser Genetics Nd3 X 50 Long Distance Green Laser Designator with Mounts Precision machined from high tech aluminum; Fully O-Ring sealed for dust and water Fully Multi-Coated optical lens system; Nitrogen charged for anti-fog Rotary optical beam collimator - allows quick adjustment of beam diameter and intensity 532nm (Green) Laser light frequency - easiest light for the human eye to see