920d Custom’s ES-335 Twenty-One Tone upgraded wiring harness will take your ES-335 from stock to rock in no time at all. It utilizes a wiring schematic made popular by a certain legendary guitarist and features four push/pull pots that will add to your pickup configurations—21 combinations to be exact. With independent coil splitting, phase control, and series/parallel switching, this harness is just enough, without being overwhelming or unnecessary.