This is Wheels Manufacturing Derailleur Hanger 391. All Wheels Manufacturing replacement derailleur hangers are produced in their Colorado shop to exacting tolerances. Features: CNC machined 6061 aluminum Black anodized finish Attaches to frame with (2) M5x10 Flat head screws Fastener Included Replaces Scott Part# 273417 Compatibility: 2014-19 Addict 10, 20 2017 Addict 15 Di2 2015-16 Addict 15 2015-19 Addict 30 2018-19 Addict RC 10 2018-19 Addict RC 20 2017 Addict RC Di2 2018 Addict RC Pro 2014-17 Addict SL