Black River Manufacturing Benelli M4/SBE 3 7/8 Round Magazine Extension Kit Carbon Fiber. It is extremely light with tough aircraft grade aluminium adapters on both the receiver and forend side of the shotgun. The magazine is available with regular stainless or black oxide stainless. This is a complete kit. The magazide tube kit comes with everything you need. WHATS INCLUDED: Carbon fiber magazine tube picatinny magazine tube clamp extended spring and follower. Specifications for Black River Manufacturing Carbon Fiber Benelli M4/SBE 3 7/8 Round Magazine Extension Kit: Manufacturer: Black River Manufacturing Color: Carbon Fiber Fabric/Material: Aluminum Carbon Fiber Gun Make: Benelli Gun Model: Benelli Super Black Eagle III Benelli M4 Gun Type: Shotgun Weight: 3.4 oz Package Contents: Black River Manufacturing Carbon Fiber Benelli M4/SBE 3 7/8 Round Magazine Extension Kit ri What firearm models does the manufacturer say Black River Manufacturing Carbon Fiber Benelli M4/SBE 3 7/8 Round Magazine Extension Kit is compatible with? The manufacturer suggests that Black River Manufacturing Carbon Fiber Benelli M4/SBE 3 7/8 Round Magazine Extension Kit is compatible with Benelli M4 Benelli Super Black Eagle IIIBlack River Manufacturing BREMTCF: Benelli M4/SBE 3 7/8 Round Magazine Extension Kit Carbon Fiber