The Isobar ULTRABLOK Premium 2-Outlets Surge Suppressor used to protect sensitive computer, networking and telecom equipment. Loaded with a generous combination of high-quality components, near indestructible all-metal case and unique noise filtration system, this Isobar offer the highest levels of protection. Robust surge suppression circuits with sine wave tracking offer extreme levels of protection against the heaviest surge conditions. Isobar's unique protection system combines large torroidal chokes, HF/VHF capacitors and multiple metal oxide varistors that remove high-level surges and EMI/RFI interference.