All Wheels Manufacturing replacement derailleur hangers are produced in Colorado to exacting tolerances. – Dropout-374 is the direct mount version of dropout-284 – Replaces specialized part #S182600003 – For use with Shimano direct mount rear derailleurs – CNC machined 6061 aluminum – Black anodized finish – Attaches to frame with (1) M5x10 socket head screw (fastener not included)