Aluminum Air Cleaner Stud Kit - 5/16" carb thread Includes aluminum stud, thumb knob, air cleaner lid mounting stop and jam nut Mounting stop & jam nut go under air cleaner lid so you can tighten the thumb knob without distorting the lid Set screw in thumb knob keeps it from coming loose - beats duct tape Built-in rubber seal keeps dust out of your engine Top thread 5/16", bottom carb thread 5/16" - Holley Specifications Material Lightweight aluminum Finish Red anodized Length 7" Top Thread Size 5/16-18" Bottom Thread Size 5/16-18"