Product details: q-tech duct collectors extract the dusty air from the dusty generating point through duct connected to the bag housethe bags are usually made of cotton, wool, synthetic, or glass fibers and there may be hundreds bags within one structurethis kind of fabric filtration is a well-known and practiced method for separating dry particles from a stream of gasesdustthe dusty gas flows into and through the fabric, leaving the dust on the inside of the bag, while the cleaned gasdust exits through the bag to the other side and then out the bag-house.