For the Mossberg M590A1 pump shotgun. Extended Picatinny rail bolts on over receiver area and integrates with an oversized safety. Designed to readily be activated during times of stress from the top and sides. Picatinny rail extends over barrel to allow for mounting of reflex optics. Channel through the center allows use of rifle front sight. Extremely durable and smooth because of its integration with the supporting end of rail.