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 chrome moly 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.