Specs All FET design Two bands of boost Maximum amount of boost: 18db, occuring at 40 Hz for the bass, and 4kHz for the treble. Input impedance: 1 meg ohm Output impedance: 600 ohm 18 volt system. Runs on two 9-volt batteries. This allows for maximum headroom. Dimensions: 2.5(W)× 1.5(D)× 2.5(H)cm