This is NOT the silk-screened Vexter pedal. This is an original, hand-painted fuzz probe. 

Has a theremin-like antenna that lets you adjust one the knobs (STAB) by moving your foot or hand close to the copper plate, making it a big favorite of experimental noise fans, with its varying oscillation pitch and strange fuzz guitar interactions.

Pedal Dimensions (LxWxH):  7.50" x 4.70" x 2.40".

From the instructions:

OVERVIEW
The Fuzz Probe is a kind of cross between a theremin and a fuzz factory. There is a 3 5/8” antenna plate mounted on a
chunk of 3/8” clear acrylic that passes over the top of the pedal housing, angles down to sharp turn, and goes back to the
pedal. Under the whole mess is a 3 5/8” by 7” sheet of aluminum that provides shielding from annoying ground effects and
wires under the stage. It also serves to protect the knobs from being knocked off if you drop it on them.

WHAT DOES THIS PEDAL DO?
Already, it should be apparent that this is the most dangerous pedal I have ever made. Ow! The antenna plate projects a field
of RF energy that is affected by your foot (or other appendage), altering the circuit that generates it, and in so doing, increasing the
brightness of that LED on the top of the pedal and also controlling the STABILITY (STAB) knob on the back. I could have made it
just control that LED, I mean, that’s enough for some people, but nooo, I went and connected it to the stability knob too. This lets
you select your favorite squealy Fuzz Factory setting (doesn’t the band love that?) and then mess around with the STAB knob with
your foot and create little melodies and interference mod