The Wolf Tooth Goatlink derailleur hanger extension offsets the position of your rear derailleur improving long-term shifting performance and making it possible to run Wolf Tooth Giant Cog cassette expanders in an optimal position. If you’re looking to climb the steepest climbs on a 1x set up, this is a hassle-free way to do so.   Compatibility Compatible with Shimano Shadow+ 10-speed / 11 speed rear derailleurs (clutch type ONLY). The GoatLink is optimized for use with Wolf Tooth’s 40- and 42-tooth GCs and all sizes of Drop-Stop chainrings - but will work with any 11-40t or 11-42t 10-speed cassette.  . Direct Mount-native frames and SRAM rear derailleurs are not supported.  . You will never need a longer b-screw with the GoatLink.   *Due to variations in derailleur hanger geometry, chainstay length, chainring size, B-screw adjustment, and suspension configuration, individual results will vary slightly.