The Sram X01 DH Rear Derailleur makes shifting softer, faster, and safer, keeps the chain in its place, and reduces bounce so you can practice mountain biking with total comfort. It has a maximum capacity of 28 teeth and includes a bearing clutch that eliminates chain bounce and bumps.This bike rear derailleur is made of aluminum, while the pulley bearings are made of steel. The X SYNC technology provides good performance, easy shifting, and silent operation. The X HORIZON allows for faster and effortless shifting. Besides, it comes with a cage lock that makes wheel removal and installation easier.The 7-speed X-HORIZON™ rear derailleur makes shifting smooth and reliable no matter where you ride. Engineered to maintain consistent chain gap across all seven gears, X-HORIZON™ eliminates vertical movement for faster shifting, reduced shift force and an end to ghost shifting. Our new, Type-3 ROLLER BEARING CLUTCH™ features a smoother torque curve for a quieter, more consistent operation and feel. The 12-tooth X-SYNC™ pulley wheel holds the chain in place, reducing bounce and chain slap. And CAGE LOCK™ technology makes wheel removal and installation easier than ever. Paired with the X01 DH 7-speed shifter, X-HORIZON™ forms the backbone of X-ACTUATION™ technology—and that means completely smooth shifting action.Features:- Updated design of the rear derailleur incorporates our proven X-HORIZON™ design and new Type-3 ROLLER BEARING CLUTCH™ technology- 12-tooth X-SYNC™ pulley wheels- Large upper pulley offset automatically adjusts chain gap- Sealed cartridge bearingsSpecifications:- Speed (RD) :7s- Cable pull ratio:Exact actuation- Cage (RD):Medium, Short- Max tooth:28- Pulley bearings material: Steel- Cage material (RD): Aluminum