Proprietary billet aluminum wheel hub kit is designed and engineered exclusively for our Arlen Ness forged aluminum wheels (sold separately), Cartridge design hub features both wheel bearings pre-set in one hub for optimum radial and lateral run out accuracy, Lightweight coped design provides form and function, Accepts factory or aftermarket hub mounted 5-bolt hub mounted rotors (3.25" bolt circle)., Hub kit mounts to your Arlen Ness forged rims in minutes with basic tools offering excellent flexibility for stock and custom applications.