Mossberg 500/590 Series Shotgun Sight Rail T6 6061 Aluminum 5.5 Inches Long with 13 Slots by Golden Eye Tactical Weaver/Picatinny rail mount for Mossberg 500 and 590 series shotguns, T6 6061 Aluminum , 5.5 Inches Long with 13 Slots Crafted from durable & lightweight 6061 T6 aircraft grade aluminum Allows for the mounting of Picatinny or Weaver Standard scopes, Red dots, magnifiers, and other optics.