MSD Ignition 8739 RPM Controls Two Step Module SelectorRPM Module Selector RPM Controls Two Step Module Selector RPM Controls Two Step Module Selector; Allows You To Choose Two Different RPM Limits That Can Be Activated At Different Times; SPECIFICATIONS: WARNING CA Proposition 65: Yes WARNING CA Proposition 65 Message: WARNING: Cancer and Reproductive Harm www. P65Warnings. ca. gov FEATURES: Allows a launch rev limiter and a high speed rev limiter The MSD Module Selectors provide the ability to switch