with the full dual qiring and 2 full seperate coils in parallell so if one blows the carto goes to ~3.2 ohms. The problem with the ones before, which were using parallell but on shared wiring, was when a coil popped they would drop to about 1 ohm and kill the mosfet. (This is all from forum/book reading...I am an amateur with electronics, not a pro yet!)