The Champion D16 spark plug is a reliable, standard, non-resistor ignition component specifically designed for a broad range of vintage International Harvester and Case IH agricultural equipment. This hot-range spark plug features an 18mm thread with a 12.7mm (1/2 inch) reach and a 22.2mm (7/8 inch) hex size, ensuring precise fitment and efficient ignition. It serves as a direct replacement for OEM part numbers such as IH 373703R91, 373703R92, and 373703R93. Compatible with numerous International Harvester tractor models including H, M, 100, 130, 140, 200, 230, 240, 300, 330, 340, 350, 400, 450, 460, 560, 600, 650, 660, as well as various combines, cotton pickers, power units, and windrowers, providing consistent performance for classic machinery.