BOX Four Rear Derailleur - 8-Speed Medium Cage Black ModelNumber=E2131 The Slayer Knee Pads set

The Slayer Knee Pads set the standard for lightweight pedal friendly and CE-certified knee pad design

Features Vent Valve Technology for super simple service if the need arises

QUIN ready - easy upgrade with the separately available QUIN chip for fall detection

Keep your hydration right between your arms and your computer at a glance

BOX Four Rear Derailleur - 8-Speed Medium Cage Black ModelNumber=E2131 The Slayer Knee Pads setPrime 9 Technology for less derailleur travel and better chainline. Less wear and improved lifespan Box One features: Adjustable Tri Pack limited slip clutch, forged inner and outer cage, Pivot Tech cable stay, sealed bearing pulleys and 3D forged linkages Box Two features: Tri Pack limited slip clutch, forged inner and outer cage, Pivot Tech cable stay, sealed bushing pulleys and 3D forged linkages Box Three features: Limited Slip Clutch, stamped