The 70's Drive Blender is two independent circuits that can be blended together to create a huge variety of tones. The pedal has a fuzz circuit and a distortion circuit. Both get dirty enough to play heavy rock with, but when they're both mixed together in large quantities the tone can get really gnarly.
The distortion circuit is great for laying down a dirty tone, and after the desired filth has been chosen, the fuzz can be used as an embellishment on top of add an edge to the tone to thicken up riffs into a pounding wall of sound.
The pedal has four knobs - the fuzz and distortion knobs are volume controls for the two separate circuits and can be used in conjunction with each other to blend them together in the right quantities. The level control is a master volume on the whole pedal. The tone control is a master tone on the whole pedal.
It has two 1/4 inch jacks on the side - one for the input, one for the output. It runs off 9v DC regulated supply and can also take an internal 9v battery.