These air filters contain highly dense fiberglass material that traps larger particles. They should be replaced every month or so and are easily disposable. While the least expensive option, fiberglass filters are designed mainly to protect your heating and air conditioning system, rather than to drastically reduce airborne allergens and irritants. <p>These air filters contain highly dense fiberglass material that traps larger particles. They should be replaced every month or so and are easily disposable. While the least expensive option, fiberglass filters are designed mainly to protect your heating and air conditioning system, rather than to drastically reduce airborne allergens and irritants.</p> 2006-06-15T12:34:44-04:00 1-fiberglass-air-filters-case-of-12 8884 Air Filters 2006-06-15T12:34:44-04:00 2006-09-24T10:49:50-04:00 Jack Lehr 1x20x20, air, fiberglass, filters 2006-06-15T12:34:44-04:00 manual 0 10658 deny 1 20x20x1" (Case of 12) 1 52.80 8884 2006-09-24T10:49:50-04:00 2006-06-15T12:34:44-04:00 manual 0 10661 deny 0 20x30x1" (Case of 12) 2 48.00 8884 2006-09-24T10:49:50-04:00 2006-06-15T12:34:44-04:00 manual 0 10663 deny 0 24x30x1" (Case of 12) 3 52.80 8884 2006-09-24T10:49:50-04:00 2006-06-15T12:34:44-04:00 9971 1 8884 2006-09-24T10:49:50-04:00 http://static.shopify.com/s/files/1/0000/4633/products/fiberglass.gif?1236945804 Title