The conduit that the wires go through from the radiator shell to the headlight and horn. This conduit set is used on the 1928-early 1929 headlamp buckets that had the 11/16" I.D. headlamp socket holder in the base of the bucket. The part of the headlamp socket that stuck out the bottom of the headlamp for these conduits to couple to was about 43/64" O.D. U.S.A.