The Humbucker is a unique solution for reducing hum on certain turntables using Grado cartridges. For the past 40 years, enthusiasts have tried various combinations of shielding and ground wires, with no success. That's because you cannot shield low frequency magnetic fields! The Humbucker employs an entirely different approach, pulling stray magnetic fields from motor away from cartridge, instead of trying to block them. This turns out to be so effective you will think sorcery is involved. On a Rega P3 turntable with an Opus 3 cartridge, hum is reduced by 15dB. That's enough to make a real difference! All you have to do is place the Humbucker on the plinth as shown, where it hides underneath platter.