One of the main requirements of TVSS overvoltage protection modules is the capability of handling a surge current pulse of 8/20 µs. For this application, EPCOS recommends the ETFV25 series with a surge current capability of 20 kA 8/20 µs. This product can cope with a surge current about 100% greater than that handled by the ETFV20 mm series. EPCOS is one of the few manufacturers worldwide to offer a ThermoFuse varistor with a 25mm disk. Its electrical parameters correspond to those of the 25mm disk varistor.