The Cobra III Marine features a return spring in the forearm. Simply pull back on the forearm and release, the spring will return the forearm forward thus closing the chamber. This makes for rapid firing in a pump shotgun. The spring can be removed and the gun will work like a traditional pump. The Cobra III Marine is also fitted with a picatinny rail located under the forearm. Removable choke system that uses Beretta/Benelli Mobil threads.