LaserMax Uni-Max Green Rail Mount Laser with Integral Rail: http://www.amazon.com/LaserMax-Uni-Max-Green-Mount-Integral/dp/
This high-visibility green laser is compact, rugged, and fits Picatinny; Mil
-Spec; Weaver Style Rails (with minimum rail length of 1.75-Inch) Battery
Type: 1/3N Lithium (2) Accuracy: User-adjustable for windage and elevation.
Wavelength: 532nm (green) Power Output: 5mW. Spot Size: 5/16-Inch @ 7 Yds; 3
/4-Inch @ 25 Yds.
Highest visibility in ALL lighting conditions. Incredibly lightweight -
weighs ONLY 1oz. with batteries
Integral Picatinny rail system to allow a wide variety of accessories to be
stacked right onto the green laser system.
Ambidextrous activation to accomodate the left or right-handed shooter.
Constructed from FRN (Fiber Reinforced Nylon) for lasting durability.
Maintains alignment after every battery change.