The NPS 50A Transfer Switch (NTS-50i) is a shore/generator transfer switch made for mobile generator installations. Its industry standard "break before make" design works alongside a hardware interlock to keep generator power and shore power from coupling. Clear diagnostic LEDs show you where the power is, so there's no need for a volt meter or for opening the enclosure to troubleshoot. Features:• Shore/Generator Transfer Switch - Built for mobile generator installations • Break Before Make - Industry standard design for safe switching • Hardware Interlock - Prevents power coupling between generator and shore power • Diagnostic LEDs - Easy-to-read indicators show where the power is • Faster Diagnostics - No volt meter needed and no need to open the enclosure • 50 Amp Rating - Designed for 50 amp applications • Compact Design - 10.38" x 6.88" x 4.5" and 7 lbs Break before make with hardware interlock Diagnostic LEDs show where the power is No volt meter or opening the enclosure