 As well as the "sports" Comet, Vincent produced a TT racing model, the Comet "Special" (a TT model with lights) and the standard Vincent Meteor which shared many of the same cycle parts.An unusual feature of the valve design for these motors was the double valve guides, and the attachment of the forked rocker arm to a shoulder between the guides, to eliminate side forces on the valve stem and ensure maximum valve life under racing conditions.The prototype series A was refined and developed into a production model B but after World War II it was the development of the series C that represents the ultimate Vincent 500 cc single.