For more than 20 years, America's leading companies have trusted Tripp Lite's Isobar Premium surge and noise suppressors to protect sensitive computer, networking and telecom equipment. With more than 15 million satisfied customers, the ISOBAR remains the world's #1 selling premium surge suppressor. Loaded with a generous combination of high-quality components, near indestructible all-metal case and unique noise filtration system, Isobars 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. UltraBlok 428 offers 2 outlets arranged with standard wall socket spacing in a cordless direct plug-in format. Mounting tabs allow permanent connection via duplex switchplate screw. Surge suppression rated at 1410 joules/48,000 amps offers high-grade protection. Diagnostic LEDs confirm power availability, line fault and protection status. Lifetime warranty with $10,000 Ultimate Lifetime connected equipment Insurance (USA & Canada Only).