Harley CV Carb Custom idle screw Stainless steel Brass knurled top 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 older model Stock Harley CV 40mm Carbs without accelerator pumps but may work with others with 4mm threads. Note there are two spring lengths .50 (1/2?) and .720 (roughly ?) this part works with the ? spring Made of 303 stainless steel. Overall length is approximately 3 inches long. American made. Please email questions before bidding. Thanks for looking. Please Note: if you are running 5 gallon Fatbob style tanks you need to check for enough clearance between the tank and the air cleaner for your fingers.