Weidmüller VPU I (Type I), VPU II (Type II) and VPU III (Type III) surge protection products effectively reduce the interference coupling that can occur from transient surge voltages, even significantly below the limits prescribed by insulation co-ordination according to EN 60664-3 / DIN VDE 0110. This means that the whole installation is exposed to fewer malfunctions. The arrestors are co-ordinated using technical means. This means that decoupling between types I, II and III is not necessary. The arrestors are tested according to product standard IEC 61643-11 / DIN EN 61643-11 and can be installed in systems according to IEC 61643-12 / VDE V0675-6-12 and IEC 62305-4 / VDE 0185-4. This lightning and surge protection device is suited for installation in power supply systems for the US market in accordance with UL 1449 Ed.4. Weidmüller offers different products depending on the particular mains network type and voltage level.