From Celestion:
The G12M Greenback has evolved over the decades but still retains its essential, sought- after tone. Angus Young has been a Greenback devotee since the early days of AC/DC. This model is voiced with additional broad mid-range attack and restrained top-end to give a forward, punchy attitude to chords and a searing lead tone without fizz. With its well-controlled low end it can be used singly in low-powered amps, or in multiples for high-power rock heads. It’s an ideal guitar speaker to bring drive and definition to modern high gain amps.
Nominal diameter: 12″, 305mm
Power rating: 25Wrms
Nominal impedance: 8Ω
Sensitivity: 98dB
Chassis type: Pressed steel
Voice coil diameter: 1.75″, 44.5mm
Voice coil material: Round copper
Magnet type: Ceramic
Magnet weight: 35oz, 0.99kg
Frequency range: 75-5000Hz
Resonance frequency, Fs: 75Hz
DC resistance, Re: 6.7Ω
Cut-out diameter: 11.1″, 283mm
Diameter: 12.2″, 309mm
Magnet structure diameter: 5.9”, 150mm
Mounting slot dimensions: 0.31″, 7.9mm Ø
Mounting slot PCD: 11.7″, 297mm
Number of mounting slots: 4
Overall depth: 5.1”, 130mm
Unit weight: 7.9lb, 3.6kg