TacStar Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension Black 5. TacStars new modular shotgun extensions provide all of these benefits while adding additional capacity to your shotgun. The tubes are machined from tough 6061 aluminum anodized matt black and include a recess for a magazine/barrel clamp. Since both ends of the modular design tube have the same thread it can be reversed to change the location of the recess for maximum versatility. Specifications for TacStar Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension: Manufacturer: TacStar Color: Black Magazine Capacity: 5 Round Gun Make: Mossberg Gun Model: Mossberg Model 590 Package Contents: TacStar Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension High Visibility Follower Magazine spring which can be cut to desired length What firearm models does the manufacturer say TacStar Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension is compatible with? The manufacturer says that TacStar Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension is compatible with Mossberg Model 590TacStar 1082239: Mosseberg 590 12 Gauge +5 Shotgun Magazine Extension Black