This is a musical instrument jointly developed by YAMAHA and media artist Toshio Iwai. I purchased this previously, but I am selling it now as I no longer use it. The firmware has been updated to the latest version. Operation has been confirmed. There is no battery leakage. An AC adapter and instruction manual are included. I purchased a new AC adapter for the purpose of confirming its operation before listing it. While I believe it is in relatively good condition, it is a used item with minor scratches on the sides, so please refrain from purchasing if you are sensitive to such things. Tenori-on Synthesizer Sequencer Rhythm machine Groovebox