Humbuckers are the second gen tech in the instrument world and were designed to fix the noise problems of the single coil. The two coils basically act as a buffer, cutting out the feedback by sending the signal through 2 polarity fields.
the most common and mislabeled pickup wire.You can commonly find these labelled as a 2 conductor. But this single conductor features a cloth "hot" and braided "ground"
the Screw coil’s start wire (red) is connected to the cloth wire. The screw and slug coil's finish wires (Black) are soldered together. With the slug coils start wire (red) and braided wire soldered to the baseplate. This style does all the hard work for you. With this set up the ground is pre-done and all you have to do is solder it to a pot casing.