These are the same IGN1A coils that everyone and their brother is selling on Amazon, Ebay, DIY and other websites. We all get them from the same supplier. They buy them in bulk for cheap (like we do) put their sticker on them, multiply the price and put them up for sale. You’ll find them all over the web for $60 to $160. It’s the same coil. Pay full price or, or buy four or more to save. The IGN1A is an OE Mercury Marine outboard engine ignition coil. These are sold under various OE Mercury part numbers: 300-879984T01 300-8M0077471 339-879984A1 339-879984T00 8M0077471 879984T01 879984A1 300879984T01 3008M0077471 339879984A1 339879984T00 Also the same coil as: AEM 30-2853 Holley 556-112 Haltech HT-020114 Pro EFI HO 8005 AMP EFI DIY Auto Tune These smart coils have a built in 19 amp igniter and is driven by a 5 volt logic type ECU output to simplify installation. No external ignition or CDI is required. They’ll deliver over 103mJ of spark energy. If you’re building spark plug wires, you’ll need HEI style plug wire ends and boots. Wiring is: A: Coil/Ecu Trigger Signal B: Coil/Ecu Logic Ground C: Ground to cylinder head D: Battery Ground E: Battery Positive Power Note1: Pin C MUST be connected directly to the cylinder head, the coil will not provide 100% power unless it’s grounded directly. Note2: This coil will overheat if operated at 40% duty cycle for excessive amounts of time. Similar to an LS style coil, the dwell time starts when the ecu applies positive signal to pin A, the coil fires when the voltage falls to zero.