The PS20 and PS40 Coils are designed to enhance the output of factory ignition systems. They fit in place of most OEM canister coils, and thanks to their lower resistance and optimized turns ratio, will produce a higher output spark when used with breaker points, amplified ignitions or with the FAST XR-I Points Replacement system. These coils will reliably deliver a high output spark through 6,500 RPM on mild street performance applications and are oil filled to keep the windings cool. Both coils are supplied with a ballast resistor which is required if you plan to fire up your original breaker point style ignition system.