Ultimate Arms Gear Tactical Mossberg 500 590 835 Persuader Maverick 88 Shotgun Weaver Picatinny Base Rail Scope Sight Mount Compatible with Mossberg 500, 590, 835 Persuader and Maverick 88 shotguns. On older versions that are not drilled you would have to tap and drill new ones. Compatible with most Weaver/Picatinny style scope rings and similar accessories. This allows some adjustment for eye relief and also accepts a wider variety of scopes, reflex sights, red dot scopes and tactical accessories. Provides a 5.5 inch long Weaver/picatinny style tactical rail with 13 cross slots. Material: Aluminum, Color: Matte black, Length: 5.5" (140mm). Easy installation- Attaches to existing holes on your shotgun with included screws.