Designed by "Vox Sound Limited" in late 1971 and signalled in "Beat Instrumental", "Music Business Weekly" magazine, and the selective VSL catalogue of 1972. At present, only a single example is known to survive.

The device was one of the first non-strobe electronic guitar tuners on the market. As described in April 1972, there were two versions: 1) A straightforward six note tuner, and (2) a unit that enabled an organ to be connected to give the necessary base for tuning.

Thanks to Martin Kelly, a surviving unit.

Vox general (selective) catalogue of 1972.

"Beat Instrumental" magazine, January 1972.

"Beat Instrumental" magazine, April 1972.

"Music Business Weekly" magazine, 4th March, 1972 - pieces on the Frankfurt Music Fair of that year.