SRAM Universal Derailleur Hanger (UDH) - Aluminum BlackSRAM Universal Derailleur Hanger Aluminum Black. The SRAM Universal Derailleur Hanger (UDH) consolidates thousands of hanger options across the industry while protecting your derailleur against chain jams by pivoting back and out of the way and slipping slightly when encountering impacts. It improves shifting performance guarantees better alignment and works with all drivetrains. The Universal Derailleur Hanger consolidates thousands of mountain bike