Improved Performance! See PDFs under 'Details Tab' below to view GX4 performance data and curves. The GX4 Pro Series, is manufactured with two technologies, Eternalast™ and Vapor Tite™. The Eternalast™ polycarbonate plastic fan housings were developed and built to our specifications for increased durability and to prevent discoloration. The Vapor Tite™ sealing technology is an induction welding process that fuses the engineered grooves/joints together. The housing is permanently bonded together, inhibiting radon and soil gas leakage. The Pro Series inline radon fans are covered by a 5-year limited warranty and are rated for commercial or residential use. ETL listed by Intertek to UL507 and CSA C22.2 Standards. Made in the USA with U.S. and imported parts.