Top Line has introduced it’s exclusive reproduction of the 12mm VW case half nut. While generic case half nuts ( and nylock nuts) must use the 19mm socket size, original nuts used the 17mm size. The smaller size of the Top Line nut helps clear big bore cylinders without modification to the cylinder’s fins. The nuts are available with or without German base washers. Economy bulk packs are also available for professional VW mechanics. Contact Top Line Parts in Anaheim Calif.