HOLLOWcage® for Shimano Ultegra 8100 12spd. Our revolutionary mono-plate OSPW design is the quietest and best shifting, oversized derailleur cage for Shimano 12spd created to date. HOLLOWcage ® OSPW has a carbon-polymer mono-plate construction with bespoke, oversized, full ceramic bearings and the most advanced silencing pulleys ever made.
