HEATERS, 1 12” wide, were originally designed to fit grooved 1 12” wide channels, earning them the name “Channel Heaters”.Stainless steel sheath– resistant to deterioration from exposure to chemicals and contaminants, Ceramic insulation– MgO (magnesium oxide)– high purity with excellent heat transfer capability when compacted, Nickel-chromium (8020) resistance wire– coiled on custom machines assuring accurate rating.