This listing is for a 383093R91, 383092R91 375679R91 Tachometer. This clockwise tachometer is for the IHC Farmall 460 560 660 Gas and Diesel tractors. The tach has a 5/8" UNF cable end and has a nice 12 volt light option feature. The light option feature you can choose to use or not to use it. The diameter is 3 3/8" (85mm). Gauge and tachometer cases are "Yellow Zinc Plated" for greatly improving corrosion resistance.