Three Stage Retard Control Great For Nitrous MSD IgnitionIn addition to the individual retard stages, the Three Stage Retard Control has an optional start retard function that retards the timing 10 Degree or 25 Degree while cranking the engine. The Three Stage Retard Control connects easily to your MSD Ignition and can be triggered from points, electronic ignitions, crank triggers or magnetic pick up distributors. It is supplied with a 2 Degree, 3 Degree and 4 Degree module and must be used with an MSD 6,