This is a Amoeba M4 complete gearbox for Gen5 M4 AEG style Amoeba airsoft rifles offered by Elite Force. A fully built and ready to drop-in gearbox with all its parts ready to go. Fits Amoeba / Ares series airsoft M4 AEGs). Comes with what is pictured. A high quality version 2 (V2) gearbox made by Amoeba.