Yamaha keyboard. Seems to still work. I’ve had this thing since the 90s. I have an adaptar for it so you don’t need batteries. It’s not the adaptar that came with it but I’ve used it just fine for the last handful of years. I have better options now and this thing is more like a toy (sounds aren’t amazing and the keys aren’t weighted), but it has provided me with countless hours of fun over the years, although it just sits unused now…so figured I should try to find it a new home!