Fits like a glove. - SureFire Benelli M4 Shotgun Picatinny Rail System M80 for SureFire Laser sights flashlights

The rail system is very easy to install. It is solid and is a great addition to the M4. Not only for adding flashlights and grips, but it also counts as a 922r compliance part. I would recommend purchasing the rubber covers for the rails, it's much easier on the hands. I purchased this after reading reviews on other systems the interfered with the gas pistons. This system appears to be shaped perfectly around the Pistons causing no interference.