... frequency:50-70Hz 3.Phase:three phase 4. Power type:AC AC Three-phase Surge Protector with 3 Wires1. Working principle HK lightning surge protection deviceIt ... Suppressor,Surge Voltage Absorber,Polymer Lightning Arrester,High-voltage Lightning Arrester,Surge Arrester,Surege Protector,Surge protective Device,Lightning Protector,Polymer Arrester,Thunder Protection,Power surge Protector ...