12V. Dual fire. With a bullet proof, fully adjustable automotive mechanical advance unit with 14 different advance curve settings. Comes with a Mallory ‘UniliteÂ®’ electronic ignition module. Complete with instructions and wiring harness. Note: To be used with carbon core spark plug wires. Do not use copper core. Note: To be used with coil(s) with a total primary resistance of around 3-4 Ohm for dual fire for street use, 4-5 Ohm may be used but can reduce performance. For race use 2-3 is recommended. Note: Flathead & Sportster models require an OEM style 32585-36 distributor retainer, which is not available through Motorcycle Storehouse. Note: All 6 volt models will require a conversion to a 12 volt electrical system. Note: See 508739 for the replacement UniliteÂ® module only.