Small Blaster Coil (PN 4573) The MSD Motorcycle coil is specially designed to be used with MSD's MC-1, MC-2, MC-3 and MC-4 ignitions. The Blaster coil uses a high turns ratio with low primary side resistance producing the highest voltage and spark energy available. The molded-in socket style towers are spaced far apart to prevent arc-over. Specifications Turns Ratio: 75:1 Primary Resistance: 2.8 Ohms Secondary Resistance: 11.5k Ohms Max Voltage: 45,000 Volts