Offered is a chrome air cleaner knob for 1984-1999 Evolution Big Twins Harleys.  of course custom application possible for clever techs.  

Custom Chrome Part #65422 ?

It is designed to replace the stock nut on the round air cleaners.  a very old installation instruction sheet is taped to the back of the package.  

INTERNATIONAL BUYERS:  Shipped through ebay's Global Shipping program only to countries on ebay's global shipping approved list.