Built-in surge indicator tells the user the surge protector is functioning properly. Integrated polarity tester checks status of the electrical power prior to use. Brighter 3-Color LED indicators, Polarity Indication, Open Ground Indication, Lost/Open Neutral Indication. Sleek, compact and portable design design with easy pull handle makes it easy to use. No installation required. Weather resistant and thermally protected, this portable unit is designed for outdoor use.