The EZ-Just mixture screw allows you to easily adjust the idle mixture on Keihin CV and CVK 40 carburetors. Designed for the CV carburetor used on Harley Davidson motorcycles, may also be installed on Kawasaki Vulcan, KLR's, and Triumph motorcycles with CVK carburetors. Has been known to work on many other Keihin CV style carburetors.