This is a Yamaha Eladra from the 1980s. I have confirmed the variation of tone and volume with the knobs in a simple operation check. You can easily create sounds with the knobs. The drum surface has some scratches due to being hit with sticks. Overall, I think there are also fine scratches and color fading, so please understand that this is a no-claims, no-returns sale. Purchased used, triggered and played with a trigger signal from a drum machine, and stored indoors in a non-smoking environment. No instruction manual, but it comes with a stand and AC adapter, which are probably genuine.