Joker Machine Finned Derby Cover For Harley Big Twin Make your bike stand out in a crowd with this Joker Machine billet aluminum finned derby cover. Made from billet aluminum and engraved with a fin design with a stunning finish. Features: This cover really adds some custom vintage styling to your bike's Primary Case! CNC-machined and engraved to a high finish and polished Made from solid 6061- T6 Aluminum (not cast) Chromed mounting hardware is included