Abstract: A heater comprising a metallic tubular sheath in which an elongate electrical center conductor is coaxially disposed therewithin. A fibrous, inorganic electrical insulation material is wrapped around the center conductor and an electrical resistance heating element surrounds the enwrapped center conductor, the heating element being coaxial with the center conductor and electrically connected thereto with the heating element and the conductor being adapted to be connected to a source of electrical power to energize the heating element. Other electrical insulation material is disposed between the heating element and the sheath to electrically insulate the heating element from the sheath and to provide a conductive heat transfer path between the heating element and the sheath. A method of manufacturing a heater is also disclosed.