Works just like the magwell on a handgun. Guides the magazine into the opening even when it's not exactly aligned. The well in use by the 82nd Airborne Division in Iraq proves this product is valued outside the competitive arena. Available in black and desert sand colors. Note: to use a 40 round PMag with the AR15 magwell, the top two ribs on the back of the PMag must be removed with a dremel tool. Otherwise, the mag will not seat properly.