COP (Coil On Plug) coils are mounted directly on the spark plugs and plugs into stock wiring. A clean stealthy appearance and the full boost of spark power since there are no spark plug wires to take energy away. Dependable and proven automotive technology. The cast aluminum cover holds the coil in place and doubles as a heat-sink for extra cylinder head cooling. Wiring is hidden in the cooling fins. Primary resistance 0.5 Ohm, like stock. Single fire, for EFI (Electronic Fuel Injected) models.