To space Fosagate audio wire connectors 2" into the saddlebag to allow for tank/compressor clearance. Normally only used on 2021-later models. Priced each. Each can be used on either the left or right side. Basic rear just requires (1) spacer, but fast rear or front+rear would normally require (2) spacers (1 for each saddlebag). Includes longer bolts.