Flanders PrecisionAire HR362402 30" by 240" by 1" Hammock Roll Air Filter (1 Pack) Last up to 30 days Effective against the following common contaminants; househould dust, as well as debris and lint Rolls are packaged in convenient carton dispensers UL class ii Available in 1-inch spun glass, 2-inch spun glass, and 1-inch polyester synthetic filter media