Ultimate Arms Gear Tactical Weaver - Picatinny Rail Mounted Mossberg 500 / 590 / 835 / Maverick 88 5 Round 12 Gauge Shotgun Stock Shot Shell Shotshell Ammo Carrier Holder Provides Convenient Access To 5 Additional 12 Gauge Shells For A Tremendous Tactical Advantage No Gunsmithing Required - Quickly & Securely Mounts And Dismounts On A Standard 7/8" Weaver Picatinny Accessory Rail Constructed Of Injected Military Grade Reinforced Polymer Innovative Push Button Release