The Twin Power XD features the battle tested cold forged Hagane Gear, X-Ship and Magnumlite Rotor. To prevent saltwater intrusion, X Protect provides Shimano’s highest degree of protection. Developed specifically for the XD series, X Protect uses a waterproof labyrinth structure that blocks any external saltwater entry. There are three models, all with nine SA-RB bearings and one roller bearing, including a compact 3000 and 5000 size, alongside a standard 4000 size.