I have had this pedal for decades. I do not remember where I got it from, but I did not get it new. Any one know what it is? It does work. I think I had to repair the 9 volt connector many years ago.
That’s a Japanese-made Sekova Big Muff. The circuit is almost exactly that of a triangle-knob Big Muff. One of these sold for stupid money a few months ago.
