The plastic surface-mounted housings of the Harmony XALK series are available both as complete housings for direct use and as empty housings for individual assembly. The robust plastic housings made of polycarbonate are ideal for universal use in industry and mechanical engineering. This empty housing in light gray/yellow has 4 holes of 22mm and can be equipped with any push buttons, indicator lights and selector switches from the Harmony XB5 series. The auxiliary switches can also be flexibly mounted on the front or on the floor.