Combining DIN rail mounted base and pluggable Gas Discharge Tube module for neutral-to-ground connections, Surge Protection Devices protect against transient overvoltages, spikes, and impulses in industrial applications. UL 1449 3rd Edition Recognized units come as single pole with 48 Vac and MCOV of 150 Vac. Factory tested for SCCR rating of 200 kA, SPDs include remote alarm contact with visual indicator that allows for status monitoring and quick reaction in critical situations.