ISOTEL ULTRA premium surge and noise suppression system prevents equipment damage and performance problems resulting from damaging transient surges and line noise. Active filter network maintains noise-free output with zero reaction / response time. Includes two line phone surge suppression and cable. Rugged all-metal, mountable housing fitted with high quality duplex style output receptacles. 6 outlets, 2850 joules AC protection level, less than 35V let through voltage, 3 diagnostic LEDs.