Genuine Tube-like sound that makes it more than your average Tube Screamer!

More gain! That was the overall goal. If you're not playing through a real tube amp, cranked for overdrive, it's difficult to get genuine tube overdrive sound. 

The original Tube Screamer pedals used an OP-AMP system, a basic circuitry that became popular for its “perfect amp” attributes. It had no distortion so it had to be overdriven or distorted by re-shaping the signal until it distorts (diode-clipping).  Clipping it a little bit gives you Overdrive. Clipping it a lot gives you Distortion.

• Input Impedance：510K ohm
• Output Impedance：100 ohm
• Power Input：Standard 9V DC, center negative >100mA (power supply not included)
• Weight：174g/ 6 oz
• Dimensions：94（L）×51（W）×53（H）mm | 3.7（L）×2.0（W）×2.08（H）inches