11 Electrical heaters and heating systems, namely, electric duct heaters, electric immersion heaters, enclosure heaters, switchgear heaters, process air heaters, bolt heaters, flexible heaters, refrigeration defrost heaters, quartzone infrared heaters, finned tubular heaters, open coil heaters, low velocity heaters, circulation heaters, tank heaters, floor and wall heaters, pipeline heaters, impedance heaters, circulation heaters, fluid heaters, space heaters, convection heaters, baseboard heaters and radiant heaters, and accessories related thereto