XR Series Coils offer 15% - 20% more spark energy than stock coils for street or racing applications where reliable, powerful ignition output is needed. The coils are constructed from premium, ultra-pure copper alloy windings, resulting in firing performance approaching 50,000 peak volts. Tested to 8,000+ RPM and almost 1,500 HP, the FAST® XR Series Ignition Coils have been proven to perform in some of the harshest street and race engine environments. Legal in all 50 states, these coils do not affect emissions and can be installed without any additional modifications.