The response from Don and Paul are correct. All harmonizers work with any midi keyboard. However, the Korg ih vocal harmonizer has been discontinued this year. They do not make them anymore, however, their new i40m module and the keyboard version, the iS35 both have harmonizers in them. If you've read my new message, the new Solton X1 harmonizer works great, but can only be used in the X1 keyboard.