Gearboxes undergo large amounts of wear and tear after repeated use over a long period of time. Whether your AEG houses a Version 2 or Version 3 gearbox, spring sets are perfect for repairing them. Most spring sets come with all of the small internal gearbox springs necessary for operation. Airsoft Megastore also carries Version 7 and even a 1911 Hi Capa replacement spring sets. Buy a set now to have one on-hand when you do need it.