SB001/002/003: caliper adapter for oversize brake discs for radial type system (postmount). El assembly may use 4 bolt, 2 for the brake caliper (front) and other 2 for fork or bike frame (rear). Two bolts included. It is recommended to assembly by a specialist and not use axial caliper adapters (IS system) for discs bigger than ø180mm. GALFER decline all responsability in case of failure due to incorrect fitting.