I can only see two wires in the pic, they say single fire has three wires to the coil. I have had Harleys both, single and duel fire. was nothing in it power wise. I also had a dual plug set up on a Shovelhead that was single fire & no power gain over single plug dual fire. just ignition does not work as hard. some double coils single fire but the set up I had used two coils separate, most coils like you have fire together