The first Super-Fuzzes were made in 1968 by Univox, and production continued until the late 70s.
The controls are:
1) Expander - controls fuzz level;
2) Balance - controls volume level.
There are two unique features of this device that set it apart from other distortion and fuzz pedals:
The first is that the full-wave rectification of the circuit produces an upper octave as well as a slight lower octave. This also gives the sound a lot of compression and gives a mild ring modulator effect.
The second unique feature is a tone footswitch that engages a 1kHz filter that "scoops" the mids, giving a very fat, almost bassy tone, unique to this circuit.