Nordic Pure 18x20x1M11+C-12 MERV 11 Plus Carbon AC Furnace Air Filters, Qty 12 Actual size of carbon air filter: 17 1/2 by 19 1/2 by 3/4 One convenient air filter - MERV 11 pleated plus activated carbon Odor absorbing activated carbon A simple solution for controlling both odors and dust particles Nordic Pure Manufacturer Direct since 1960 - Made in the USA