These MSD Ford 4-tower style coil packs are a direct replacement for your factory coil packs. You will get higher energy and voltage outputs, plus arc duration. They are sold individually and are very easy to install. Coil Style: Coil pack Primary Resistance: 0.530 ohms Coil Internal Construction: Epoxy Maximum Voltage: 40,000 V Turns Ratio: 83:1 Secondary Resistance: 12.8K ohms Coil Wire Included: No Ballast Resistor Included: No Coil Color: Black/Red Coil Shape: Square Application: 1996-1998 Ford Mustang Cobra and GT 4.6L 1991-1993 Ford Mustang 2.3L 1995-1998 Modular 4.6L SOHC & DOHC