Mallory's series of ProMaster Ignition Coils are designed for today's specialized ignition requirements. These coils are engineered for faster rise time and longer spark duration for increased performance. The rugged, glass-filled polyester case, along with oil filled construction, assures long life and no energy losses due to arcing. RPM figures may vary depending upon the type of ignition used and state of engine tune. All ProMaster coils include brass contact terminals and a spark plug type secondary post for better coil wire retention.