The G4 axle carrier is the highest quality carrier available. Produced with T-6061 aircraft grade billet aluminum & then machined using 6-axis CNC machines. Completely assembled with top quality Japanese bearings, seals & it’s signature 4130 chromoly center tube to prevent bearing failure due to tube spacer collapsing under load. The G4 axle carriers are by far the most durable bearing carrier available today & all made in America. (Comes with adjustment tool) endorsed by Companies like Goldspeed Products, Pro Atv and us here at GPS offroad products.