The Tone Bender MKI.V was manufactured by the Sola Sound Company and first appeared in February 1966. Unlike its younger sister, the MKI, its circuit consists of two OC75 transistors instead of three. This configuration is similar to the Fuzz Face circuit.
Many artists used the Tone Bender at that time, such as Jeff Beck, Jimmy Page, Mick Ronson, and it is very likely that the MKI.V was used when recording the album of the Beatles, Revolver.