All billet CNC machined aluminum choke knobs for Keihin CVK carburetors and CTK EFI. Simply unscrew the existing black plastic unit found on your stock carb and install one of these Joker knobs in its place. This product includes stainless steel threaded stud, and the alignment of engraving is achieved by using a special serrated belleville washer. Notched cuts on outside really improve grip of the knob. Made in the USA.