ditto what bruce said.
I can count on one hand how many 'burnt out' ignition condensors i've ever encountered.. and still have enough fingers left over to open a door knob.
if you are 12v and a side distribuitor type engine with a regular cylindrical coil. go with that napa ic14sb.. it's good to go.
no internal or external resistor. it is simply would witht he correct gauge and length of wire to make it correct for a 12v application.