Electrical Management System (EMS) helps to protect your RV against voltage fluctuations, power surges and incorrectly wired shore power which can cause sever and costly damage to RV appliances and electronics. 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.