The Celestion G12M Greenback Speaker, with a 16 Ohm impedance, was Celestion's inaugural guitar loudspeaker to incorporate a ceramic magnet structure. Offering nearly the same magnetic flux to the voice coil as the Alnico version, the Greenback did so in a significantly smaller package.

Consequently, it set the stage for compatibility with high-power amplifiers, while the ceramic magnet contributed distinctive tonal qualities. Known for its robust and commanding presence, the Greenback excels when paired with an overdriven valve amplifier. Over time, the speaker has been refined but continues to deliver the classic woody tone with a powerful impact.