An ergonomic laser sighting system. Easy to install and easy to use. Comes with all eqipment necessray to do a proper installation. Has a great fit on my Glock 19, the whale tail gives you a stable shooting platform. A choice of continuous or pulsing Laser, a selector switch and easy activation button in the web of your hand. Adjustable for elevation and windage. Only downside is holster selection. Holsters with a strap that goes over the end of the slide, may not fit. More information availible at lasermax.com