Never been ran. Only purchased on umbrella aurmory website. Decided to go polarstar HPA system Surplus VFC V2 Complete Avalon Gearbox Front Wired sig sauer mcx m4 VFC stock gearboxes, V2 type. Pulled from VFC AEGs we upgrade, excellent back up or base for upgrade PRODUCT DETAILS V2 style 16:1 SSG Fits most compatible AEG Ambi/standard selector ready ECS/MOSFET avalon gearboxes only Small type Tamiya 8mm bearings MATERIAL Aluminum gearbox Steel gear and spring Polymer compression assembly DISCLAIMER Surplus item (not new, sales are final) FRONT WIRED MCX WILL NOT COME WITH A SPRING GUIDE OR SPRING