SRAM UDH HANGER BLACKThe Universal Derailleur Hanger or UDH consolidates thousands of mountain bike derailleur standards Offers unparalleled derailleur protection and perfect alignment, guaranteed The UDH is designed to rotate rearward in the event of impact and features the ability to re rail the chain back onto the small cog Works with all commercially available MTB and E MTB drivetrains including Shimano, Box and Sunrace *Compatible with frames designed for its use