Ribbon Switches are suitable for applications ranging from general purpose switching to safety-critical sensing. They are available in a wide range of pressure sensitivities, sheathing materials, lead wire combinations and colors. They exhibit substantial resistance to moisture and chemicals. It is constructed from two strips of metal in the form of a ribbon separated by an insulating material. It is constructed so that when an adequate amount of pressure is exerted in any place along the ribbon the metal strips make electrical contact. These are available in lengths up to 20 feet, but the switches used in pressure mats or runners are about 2 to 3 feet long. The series of switches forming the mat are electrically wired in parallel and the assembly is sealed between two plastic sheets.