Quartz emitters provide medium wavelength radiation and can be the most preferred source of heat when rapid heater response is needed. The heaters are comprised of a series of quartz tubes running parallel to each other within a highly reflective aluminized steel housing. Each tube contains a coiled resistance wire available in a variety of wattages and voltages. Watt densities up to 30 w/sq. inch (4.65 w/sq. cm) are available. The large variety of sizes, shapes, and watt densities allows quartz emitters to be highly useful in zoning arrangements such as plastic thermoforming sheet-fed applications where complex heating patterns are needed, high-speed roll-fed processes, and machines requiring precise zone control because they are small in size, and can easily be put in larger panesl.