Named for its 0.375 in. (9.5 mm) thickness, the rugged Watlow 375 strip heater is capable of both high temperatures and high watt densities. Watlow begins construction by accurately placing a coiled, nickel-chromium element wire in the center of the heater. The element wire is then embedded in magnesium oxide (MgO)-based insulation compacted into a solid mass creating excellent heat conductivity and high dielectric strength. The heater is then enclosed in aluminized steel or 430 stainless steel sheathing.