Helps to protect your RV against voltage fluctuations, power surges and incorrectly wired shore power. Improved design features include: state-of-the-art microprocessors, all weather shield assembly, rugged pull handle, secure locking bracket, built-in scrolling digital display and a tough Lexan® housing. Sleek, compact portable design makes unit easy to use and store. Plug-and-play application. Designed for recreational vehicle use only.