Champion RJ12YC Spark Plug 0.033 to 0.038 in Fill Gap 0.551 in Thread 0.813 in Hex Copper For: 4-Cycle Engines

RN9YC & RN11YC4-32: Resistor plug, 14mm, 3/4 in reach, 13/16 in hex head, projected tip, copper core. RJ12YC resistor plug, 14mm, 3/8 in reach, 13/16 in hex head, standard projected core nose, copper core design.