Early 1970s Univox SUPER FUZZ. This is a very sweet pedal, with a wealth of usable OD/distortion/blown out fuzz sounds in it. This is an indispensable tool for use in and out of the studio - Great on guitar, bass, synth, and drum machines.
Running this thing with a dying battery gives it a whole new dimension and I highly recommend messing around with the voltage to see where you like it best - or even use it with a variable power supply :)