For use with 120/240V 50/60 Hz 16A Supplies. Correctly installed the galvanic isolator will block galvanic currents in the shore earth connection up to 1.1V. Above this level current is allowed to pass maintaining the safty earth connection. For almost every combination of metals likely to be found at a mooring the 1.1V maximum is sufficient to block corroding currents. when the voltage at the earth connection is greater than 1.1V, current is allowed to flow through the galvanic isolator potentially corroding submerged metals on the boat. In this situation the shore power should be disconnected to avoid hull corrosion. The meter shows PASS- the voltage is below 1.1V, and FAIL- the voltage exceeds 1.1V. When the indicator is within the GREEN zone the galvanic isolater is blocking D.C. galvanic currant. D.C. galvanic current can also be caused by other shore earth connections such as telephones and cable televisions. PRODUCT SPECIFICATION amperage (A) 16A supply dimensions width: 140mm (inc mounting hole tabs), depth: 55mm, height: 65mm voltage (V) 120/240V, 50/60hz supply additional information correctly installed the galvanic isolator will block galvonic currents in the shore earth connection up to 1.1V