20" X 25" X 1" Hvac Furnace Filter By Castle Filters, One-Year Filter. The Castle air filter is a new innovative HVAC filter that will last up to a year. This new filter will collect as much dust as 20 regular pleated filters. High air-flow with an open-cell, triple-layer core with a tacky media for collecting dust removes 93% of the most harmful airborne particles in your home ( 5 microns). Treat yourself and your HVAC system to longer lasting filtration. Patented Filter Technology: Castle Filters use 3 layers of OE-inch open-celled foam, with a patented tacky center layer that catches dust like fly paper. Proudly made in USA - US patent #10,183,249 B2 MERV 8: The High-Flow MERV 8 air filter effectively removes 93% of the most harmful dust particles and offers superior protection of your equipment and home while still allowing maximum air-flow HVAC Filter: Castle Filters have 400% more surface area for dust and other particles to collect. The internal foam is treated with a sticky material to collect more dust while letting the air pass through Lasts One Year: The furnace filter holds up to 20 times more dust than a pleated filter. While pleated filters need to be replaced about once a month, the Castle Air Filter lasts one year which is 4-12x longer than the others Save Energy and Lower Land Fill Contribution: Castle Air Filter helps you save energy with its advanced filtration technology and also helps in generating less waste as it need not be changed every month like a standard filter