Abstract: A harmonica is provided with three diatonic reed harps vertically aligned in a single housing. The three diatonic reed harps are in communication with a central mouthpiece. The reed harps are in different keys. Two movable sliders block the air channel to two of the three reed harps at any one time. The sliders are caused to move to blocking or unblocking positions through the actuation of a pair of buttons. The first button and the second button engage and disengage elongated slide members which are aligned in horizontal relation with each of the three diatonic reeds, either blocking or unblocking the air passage therethrough, thus preventing their ability to make sound. Through manipulation of the pair of buttons, the user may select any one of three harps to play. When both buttons are disengaged, the central harp is open, and the top and bottom harps are blocked. When the front button is engaged, the lower harp is open, and the top and middle harps are blocked.