G2 Master kits include all the parts that are needed to properly install a ring and pinion. These G2 kits include hard to find parts like a proper shim kit, replacement pinion nut , crush sleeve, pinion seal, pinion bearings, carrier bearings, ring gear bolts, silicone sealer, Loctite and gear marking compound. these are the parts that the auto parts store never seems to have or ever herd of.