An unusual plug featuring a ball end and a through hole to drain fluids The shaft of this one starts at 6mm and then tapers up to 11mm at the end; this then drops off with a shoulder back down to 6mm. This dropoff is the bit that should help retain the plug. Size: - Total length: 87mm - Insertable: 69mm - Ball diameter: 18mm - Shaft diameter: 6mm upto 11mm Material: Stainless Steel