WEM was one of the first major companies in the UK to offer commercial fuzz boxes, and based on the number of surviving examples (and despite being a relatively crude-sounding two-transistor design) the WEM Rush Pep Box seems to have sold reasonably well between 1965 and 1967. By the late 1960s, however, WEM went on to offer a far more sophisticated fuzz box, in the form of the Project V.
In addition to the typical controls (for the output volume of the pedal, as well as the amount of fuzz produced) the Project V featured ‘drive’ and ‘edge’ toggle switches to further tailor the fuzz sound. The Project V also included two internal trim pots.
The origins of the Project V may be found, at least conceptually, in the WEM ‘Fifth man’ guitar (which was advertised in a 1967 Bell catalogue) and featured recognisable controls for the ‘drive’ and ‘edge’ of the Project IV effect. Whether the electronic circuit of the Project V fuzz box is similar to that in the ‘Fifth man’s’ Project IV feature is unknown.
Early examples of the Project V date to 1968, but date codes on parts inside pedals alone aren’t sufficient for ascertaining when production began, because the Project V was not advertised until the following year. Most surviving examples feature potentiometers dating to 1969. Pictured below is an early advertisement for the WEM Project V, as printed in the 1969 Bell Musical Instruments catalogue.
The circuit board of the WEM Project V featured 8 silicon transistors, and was far more sophisticated than most of its contemporaries.
Individual battery contacts and a pair of slim Terry clips were screwed into the underside of the wooden frame of the pedal and, according to a testimony from the original owner of a Project V, the unit ran off a pair of cylindrical Mallory batteries, connected in series. It is unknown whether the pedal was originally designed for use with a pair of 4.2, or a pair of 8.4 volt batteries. Because part of the Project V’s circuit is based off a textbook quasi complementary amplifier, it is distinctly possible that the pedal was designed for a higher voltage supply than the typical 9 volt battery seen in other fuzzboxes.
Many Project V fuzz boxes were also crudely numbered with felt-tip pen on the inside of the bottom plate, but it is unknown how many units were produced in total.

Two well-known users of the Project V include Paul Rudolph, of Deviants & Pink Fairies fame, as well as Brian Eno. Rudolph confirmed via private correspondence that it was in fact his WEM Project V that was either loaned to Eno, or left behind at the studio, following the ‘Here come the warm jets’ sessions.
Pictured is Paul Rudolph, performing on an unknown date, at an unknown location, with a WEM Project V. This is the exact pedal that Brian Eno would go on to describe using for some of his guitar treatments during the 1970s.1 (Photo credit unknown)
Thanks to the P. Beard, S. Castledine, M. Keeble, H. Barclay, the WEM Owners Club [https://www.wem-owners.com] & Paul Rudolph
I have built a replica from a counter balance tool box tray