The XLK-5 lower manual (with same key action and multi-contact system as the XK-5) converts the XK-5 into a portable dual-manual Organ. Its vertically extended side panels replace those on the XK-5, creating a gapless dual-manual organ that can be carried as one piece. If you are a B-3 player accustomed to dual manuals, this is a logical addition to your XK-5.