Nearly twenty-three million 9.5 mm diameter Pencil Nozzles have been sold in its short twenty year history. Through the years, the design changes have kept pace with the increased performance demands of the small and medium sized diesel engines. Installation details are simpler and less costly than conventional nozzles, including locations beneath the engine valve cover. Standard servicing techniques for this unique design have been in use since the beginning. The new Slim Tip (5.4 mm diameter) version offers additional installation advantages as engine bore diameters decrease and speeds increase.