SHS Steel AEG Gear Set 18:1 gear ratio (Standard) -  These are good quality, affordable, and made out of steel.  They are much better than most stock AEG gears.  Want a more reliable set of gears so you can run a LiPo?  Or just need to replace a broken set of gears and want the most reliable set that won't break the bank? Buy this set!  Fits most version 2 (M4, M16, etc.) and version 3 (G36, AK, etc.) mechboxes.  Includes one each:  spur, bevel, sector gears.