The Flanders Bulk Media Series 1T20 Air Filter Media Roll is a 20" wide X 90' long X 1" thick four denier tackified air filter media roll constructed of polyester synthetic fiber. The fiber media is durable and moisture resistant making polyester synthetic fiber media an ideal alternative to spun glass media. The 1T20 roll offers a high arrestance and dust holding capacity making it ideal as a pre-filter for high efficiency filters. Product Features Polyester Synthetic Fiber Media This durable, moisture resistant media prevents potential damage from stress and dampness, extending the service life of your filter. High Arrestance Media with high arrestance are able to remove high quantities of dust from the air. High Dust Holding Capacity A high dust holding capacity extends the service life of your filter by allowing it to retain high quantities of dust before replacement.