BOSS OC-2 ACA specification Octave. I had this as a sub, but I'm selling it due to equipment replacement. Photo 8 shows a comparison between the Japanese and Taiwanese versions. (The item for sale is the Taiwanese version). The usage is almost the same. The op-amps are also the same, with only differences in resistors. I compared the sounds, but I couldn't tell the difference. Operation has been confirmed with an adapter and batteries. Please use an ACA specification adapter for the adapter. Operation has been confirmed with a DC adapter and a 9v battery. Notes: Please take a close look at the photos and confirm any scratches or stains before making a purchase. Please refrain from purchasing if you are overly concerned about these details. This is a used item that has been stored and used by an individual, so please refrain from bidding if you are looking for a perfect item. No returns or exchanges, please.