Standard sheath material is 321 Stainless Steel which provides good thermal conductivity, and resistance to corrosion and scaling. Welded end disc made from the same material as the sheath provides a positive seal against moisture and other contaminants. Grade “A” Nickel-Chrome resistance wire precisely wound on a high purity magnesium oxide core places the resistance wire as close to the inside of the sheath as possible. A high purity Magnesium Oxide (MgO) powder is used to fill all remaining space inside the sheath. Heater is then swaged, which compacts the magnesium oxide grains into a solid mass. The standard termination for is Type N, 10" (254 mm) long nickel conductor lead wires externally connected to solid conductor terminal pins.