Excel Dryer housed filter media individually tested for a certified efficiency of 99.97 percent filtration of bacteria and particulates at 0.3 microns per the established test protocol IEST-RP-CC001.3. The filters are serialized and date-coded upon passing this test. Certified HEPA filtration system measures 8-5/8-inches width by 4-1/8-inches height by 2-3/16-inches depth, 0.44 pounds. Designed to easily retrofit into any Xlerator high speed energy efficiency hand dryer. Backed by a 1-year warranty. Made in the USA.