Firerod cartridge heaters have nickel-chromium resistance wire to ensure even, efficient distribution of heat to the sheath. Conductor pins offer electrical continuity, and magnesium-oxide insulation of specific grain and purity results in high dielectric strength and faster heatup. The Incoloy sheath resists oxidation and corrosion. UL-listed and CSA-approved flexible stranded wires are insulated up to 480oF (250oC). Circle 220, Watlow Electric Mfg., (314) 878-4600,