This is a vintage 1968 UMI (United Musical Instruments) Buzz Tone & Volume Expander electric guitar effects pedal. This particular example is in very excellent 100% all original condition and includes the original box! Innately scarce, it would be difficult to find a better example of the Buzz Tone fuzz pedal.
The UMI Buzztone “Expands” upon the typical fuzz pedal, allowing for two different stages of overdrive. The first stage, which cannot be bypassed, is essentially a volume boost. Once the pedal is engaged the contour controls the tone, and the buzz controls the amount of fuzz. This simple circuit with (2) germanium transistors is extremely unique, and really sounds unlike any other fuzz produced at the time, so whether you fancy yourself a fuzz fanatic, or a collector of special musical tools, this is definitely something worth owning.