Warman G-rail triple coil electric guitar pickup - A very special pickup indeed. 3 coils, ceramic and alnico magnets. This is the simplified 4 wire version

 

This is a standard humbucker sized unit that will fit in place of most humbuckers. It has two coils wound as hot rails with a strong ceramic magnet powering these that lifts the treble whilst retaining all the power, bass and mids. The rails have their own individual output wires so is in effect a fully fledged twin rail humbucker in its own right.

 

Mounted on the same chassis is another coil wound with 6 individual alnico magnets again with its own output wires so we're looking at three coils and six output wires plus the shield.