MRP Ramp Control Cartridge Model F - For Rock Shox Zeb 2020+ 27.5"/29"MRP Ramp Control Cartridge Model F For Rock Shox Zeb 2020+ 27. 5" 29". Ramp control adds speed sensitive ending stroke bottom out adjustability to forks. At high shaft speeds the cartridge it mimics the addition of volume reducing spacers in the fork. At low shaft speeds it allows the fork to be more active. Adds speed sensitive ending stroke control and bottom out force adjustability Isolate and tune bottom out with minimal changes to initial and mid