Camco's 5500W 240V screw-in foldback type ultra low watt density water heater elements are better suited for areas with problem water (hard water, lime, etc.) premium ultra LWD Lime Life elements carry a limited 5 year warranty. Ultra LWD and special metal surface (high performance nickel-chromium stainless steel alloy) reduce chances of lime build-up. They resist dry firing and are ideal for problem water areas and locations with intermittent water supply.