Mu-Tron Micro-Tron IV envelope filter (serial MT4-VINTAGE-0000744) - the compact modern Mu-Tron from Mike Beigel, the man who invented the original Mu-Tron III. Real Mu-Tron opto envelope filtering with low-pass, high-pass and band-pass modes, a Lo/Hi range switch, Level, Peak (resonance) and Gain controls, plus an Up/Down footswitch to flip the sweep direction on the fly. CV in and CV out let it control, or be controlled by, other CV gear. From Stevie Wonder clav funk to bubbly bass and synthy guitar quack. CONDITION NOTE: there is one small paint chip on the face, about 3mm, just above the left LED (close-up in the photos). It is cosmetic only; the graphics, controls and switches are unaffected. Otherwise very clean, with velcro on the bottom. Fully working. From a smoke-free project studio. Fully tested and working. Carefully packed, shipped fast with tracking & insurance. Studio liquidation - bundle deals welcome.