Tripp Lite's Isobar Surge Suppressors are one of the world's highest selling premium surge suppressor, with over 18 million in use. Isolated Filter Banks: the Isobar is the only surge suppressor that features internal filters (known as "Isolated Filter Banks") located between its outlets that provide an additional level of protection against line noise distortion. Other surge suppressors protect connected equipment from line noise generated outside the surge suppressor (by an air conditioner operating in another room, for example). The Isobar is the only model that protects equipment from line noise generated by devices connected to the same surge suppressor. For example, a user may have a computer and a printer plugged into the same Isobar Surge Suppressor. Even though the printer generates interference, the computer is unaffected, because the Isobar has filtered the line noise. All-Metal Housings: Isobar's rugged, industrial-strength all metal case safely contains the strongest surges and stands up to every application. The Isobar is available in a variety of outlet, cord and case configurations. Isotel models feature tel/modem surge protection. Up to $50,000 Ultimate Lifetime Insurance covers connected equipment against surge damage for life!