The Screw in Air Bleed has a 10×32 threaded. Air Bleeds are Sold in pairs. You can Pick your size from the drop down menu. Blanks are available as well. All Carburetors use Air Bleeds to allow the correct amount of air that is allowed into the idle, transition, and main circuits. Holley Brawler, 4150hp and 4500hp, and QFT carburetors use this style of threaded air bleed.