All E-bodies came with the corrugated (collapsible style) adapters and when models such as Vialiants, Darts, Satellites, Coronets etc. were ordered with the rimblow or tuff wheel option the smaller smooth adapter had to be used. The reason is that in these models the standard steering wheels were built longer (deeper). So to keep the Steering column distance correct when the flat rimblow or tuff wheels were ordered this spacer was required.