This replaces the idle screw and lets you adjust the idle while you are on the bike without using a screw driver. If your bikes idle changes in different weather or if you want to warm it up without running the choke and loading it up, this works great, it is made for Stock S S super E Carbs but may work with others with 8-32 threads. If you are looking for a little dress up for a custom bike this may be something to consider These are Made of stainless steel and brass. Thanks for looking. Overall length is approximately 3 inches long. American made. Please email questions before bidding. Thanks for looking. Please Note: This idle screw will not work with after market Enrichener Knobs, and if you are running 5 gallon Fatbob tanks you need to check for enough clearance between the tank and the air cleaner for your fingers.