WP APEX PRO 8500 Cartridge Kit 1390 Super Duke RAPEX PRO 8500 CARTRIDGE CNC milled from high strength aluminum Improved contact with the ground Closed cartridge technology Later braking and earlier acceleration possible Greater comfort Greater stability Motorsport expertise for the street Improved response and feedback from riding surface in every riding situation Front fork springs need to be ordered separately. Fork Spring Option New fork springs are required when installing the 8500 kit. We give