Rubber offers more vibration absorption over polyurethane, which results in longer ride times before hand-fatigue sets in. Dimensions: 9/16” ID, .885" OD, 1-1/4” Flange OD, 3/16” Flange Thickness SOLD AS A SET OF 4 Fits 1984+ Harley Tour Glide FLT, Electra Glide FLHT, Road Glide FLTR, Road King FLHR, Street Glide FLHX & 2018+ Softail Models. Replaces HD# 56161-83A.