This is a Yamaha electronic drum set produced in the 1980s. I have confirmed the variation of tone and volume with the knobs through simple operation. It has a built-in sound source, making it a rare electronic drum set that allows for easy sound creation with knob operation. The playing surface has some scratches, likely from being hit with sticks. As it is old, I believe there are also fine scratches and discoloration overall, so please understand that it is sold as-is, with no returns. I purchased it used and triggered it with a trigger signal from a drum machine, and have stored it indoors in a smoke-free environment. There is no instruction manual or AC adapter. Shipping will be on the weekend, so thank you for your understanding. The original AC adapter (AC-10) was labeled as follows: INPUT AC100v 50/60Hz 8VA OUTPUT DC12v 200mA