Includes 24″ long wires with pre-attached 90º plug boots (with double interlocking connectors) and two 180° (straight) coil boots and connectors. Cut to length required. Spiro-Pro core. Compatible with both electronic and points style ignitions. The special spiral wound ferromagnetic core provides resistance, 350 Ohms/ft., for electronic ignition systems and increases output. The Spiro Pro core provides over 10 times the power output when compared to a carbon core. Note: Some electronic ignition manufacturers do not recommend using spiral wound core cables. Check the instruction manual of your electronic ignition module for more information. When in doubt it is advised to use suppression core cables for electronic ignition set-ups. Note: If required, 90° (MCS 941256) and 180° straight (MCS 941257) coil boots & terminal connectors are separately available to use these spark plug wires on 99-17 (Twin Cam) style coils.