Introduced sometime around 1973, the MXR Distortion+ quickly gained widespread use for its ability to push a Marshall amp exceedingly well. The most notable of course was Randy Rhoads, who used one frequently during his stint with Ozzy Osbourne before his untimely death.
This particular example dates to 1975 based off the pot codes. Paint is fairly worn on the outside, but for a pedal this old it still looks pretty damn good! Sounds like you'd expect when plugged in, and really exceeds when pushing an amp already breaking up. Only thing missing is a couple of backplate screws.
