This Harley Davidson 4-speed fill plug tool you can use to loosen the original fill plug with a slot on a Harley Davidson 4-speed transmission. You place the Harley Davidson 4-speed fill plug tool on the fill plug with the raised edge of the Harley Davidson 4-speed fill plug tool into the slot of the fill plug. Now you can unscrew the Harley Davidson 4-speed fill plug. This Harley Davidson 4-speed fill plug tool is CNC milled from high-quality aluminium, polished and then red anodised.