This Indoor/Outdoor Electric Spa Heater comes with a robust, incoloy sheathed heating element. The top of the element is 3/16 Inch stainless steel, again, ensuring a rust free environment. The heater's brass headers prevent rust stains from harming your pool or spa’s surface, giving you years of trouble-free swimming pleasure. They also allow for a corrosion free connection to your spa plumbing, making any future servicing a snap.