This is the Maxon AF-01, a vintage effects pedal considered a classic. It's an auto-filter from the 01 series manufactured in the 80s, and it has a powerful sound reminiscent of the MU-TRON. I've confirmed it works with a battery. There's a slight crackle when adjusting the PEAK slider. The exterior is in player's condition with some scratches and dirt, but there are no issues with its functionality. It's a rare item, and it comes with the original box and instruction manual, and the unit itself is fully functional. How about taking this opportunity? #Equipment #SortingOutMyParentsHouse #LimitedTimeSale