The Viper utilizes an integrated universal mounting footprint that will work on most shotguns that have a drilled and tapped receiver. All needed mounting hardware is included, and no additional mounting plates are required. The Viper has three mounting locations. The Rear Mounting Hole, the Rear Mounting Channel, and the Front Mounting Channel. For proper installation you will need at least two mounting screws, one in the Rear Mounting Hole and one placed within the Front Mounting Channel. A third and fourth mounting screw can be used as your setup allows with a second screw within the Front Mounting Channel and/or one in the Rear Mounting Channel. | Vortex Viper Enclosed Red Multi Reticle Shotgun Dot Sight