This listing is for a complete rear master cylinder assembly. The master cylinder has been polished and chrome plated with a durable finish. This master cylinder has a 11/16” Bore like the OE unit. Use with DOT 5 brake fluid ONLY. Fits 1991-2005 Harley Dyna FXD Super Glide, FXDWG Wide Glide, FXDL Low Rider, FXDS Convertible, FXDC Dyna Glide Custom , FXDP Defender Police, FXDB Daytona & Other 1991-2005 Dyna Models Replaces HD# 42474-90A