The Sierra 18-5436 Ignition Coil features 3.0 OHM operation. Designed to be interchangeable with the following: Mallory 9-29707, Volvo Penta 35254. Each Sierra product meets or exceeds the original equipment part it replaces. Resistor: Internal, For: Mallory Applications, Primary Resistance: 1.4±15% ohms and Secondary Resistance: 8±20% ohms.