Replaceable filter bag for use with the Festool CT 44 Dust Extractor that captures and contains 5.3 gallons of dust and debris, helping you work cleaner and more efficiently. Festool filter bags act as the primary, or first stage filter, trapping particles down to 5 microns in size. With a double layer of filtration made of tear resistant material, and a cap to seal it for disposal, filter bags are a must for optimum performance and convenience. Filter bags prevent dust from reaching the main filter of the dust extractor, thus greatly extending the life of the main filter and dust extractor. Made from a fleece like material which is less prone to punctures.