The ECHO1 SOPMOD M203 BB Grenade Launcher can fire most brands of BB shower grenade shells, including most Mad Bull brand shells. The launcher also comes with all the necessary equipment required to mount it on Classic Army or tokyo Marui Model 4/Model 16 type rifles. The body is constructed with ABS polymer and includes a metal barrel. The short barrel is designed after the SOPMOD grenade launcher used by many special forces organizations.