Made from carbon fiber our magazine tubes are extremely tough this is a full length magazine replacement for the M4 / SBE 3 also extends the capacity of the magazine on the civilian version to 6+1 (3" shells) 7+1 (2 3/4"). It is extremely light with tough aircraft grade aluminium adapters on both the receiver and forend side of the shotgun. Weight is 3.4ozThis is a complete kit. The magazide tube kit comes with everything you need. FeaturesMaterial: Carbon fiber, aluminum alloyCapacity: 6+1 (3" shells) 7+1 (2 3/4")Compatiability: Benelli M4, M4 clones, SBE 3 IncludedCarbon fiber magazine tubepicatinny magazine tube clampextended springfollower