Vintage 1970's Musitronics Mu-Tron Micro V Envelope Filter.

Mu-tron Micro V is an advanced envelope-controlled filter device designed specifically for the musician who wants the touch-controlled wah effect pioneered by the original envelope follower, Mu-tron III – but who doesn’t need all the effects it is capable of producing. Mu-tron V uses a sophisticated solid-state circuit design to achieve simplicity and ease of operation without compromising sound quality. On the Mu-Tron Micro V, there are only a filter range switch and a continuously-variable filter-range/sensitivity control. However, these two controls allow a wide range of effects suitable for a funky bass guitar, a screaming lead guitar, or anything in between – including electric keyboards and electrified wind instruments. The circuitry of the Mu-Tron Micro V is contained in a very compact and rugged housing of painted steel and heavy-gauge aluminum. Power is supplied by an internal 9-volt battery (not included). An optional external 9-volt AC adapter may be connected via the mini-jack provided on the Mu-tron Micro V