KORG volca keys. Sound output was confirmed from the line output using an AC adapter; operation has been verified. (Battery operation and built-in speaker have not been checked.) Included items: volca keys unit, AC adapter (KA350) Free shipping via Rakuraku Mercari delivery service. I cleaned it as much as possible, but some dirt may remain. Please refrain from purchasing if you are concerned. As time has passed since the purchase, there may be crackling when turning the knobs or moving the jacks. Also, as this is a used item, please understand that it is non-refundable and non-returnable. No complaints, no returns.