Classic 1970's music effect, most commonly used with guitar, generally referred to as a "Talkbox." The unit is placed in the output signal chain from the instrument amplifier output, before it reaches the main speaker. An internal compression driver reproduces the speaker level signal and sends it up flexible tubing where it enters your mouth, and passes the original signal out to the speaker.. As you change the shape of your mouth as if speaking or singing, the signal is filtered to produce an altered effect that mimics talking. This audio is picked up by an adjacent vocal mic. Some artists who used this effect were Peter Frampton in the seventies on the song "Do You Feel Like We Do," and Richie Sambora (with Bon Jovi) in the eighties on "Livin' On a Prayer....", and Roger Troutman of the band "Zapp" , whose music was heavily sampled in the West Coast Hip Hop scene.

This unit is the early, first version from Electro Harmonix. The case has small scratches in several places and some of the screws have small patches of rust in places, but the unit is in pretty good shape for an approximately fifty years old rock and roll piece of gear. It has an internal light bulb (typical auto headlamp type) that helps you set the output of your amp so that it doesn't overload the compression driver. The voice tube is black plastic and is in good shape. Replacement tubing is available on Reverb if you want to start fresh.