Hayward electric spa heaters contain all of the sophisticated features and capabilities of heaters twice their size. The electric heaters fit into compact spaces, even under spa skirts or steps. Like all Hayward heaters, they are easy to install and service. This heater is perfect for hot tubs and spas. For spas above 70 gpm, an external by pass is recommended. The 11 kilowatt model operates at 240 Volts, and features 304 stainless steel tank, threaded head, safety sensor electric heating element, and a heater on indicator light. The service-ease design gives simple access to internal controls.