There are several types of sewing/stitching bag sealers; plain, tape, and fold over. A plain sewing machine has a bag fed into it by a person, and the machine automatically starts stitching, and then cuts the thread when the bag is finished. A tape sewing bag sealer works similarly to the plain sewing bag sealer, except that it feeds and sews tape onto the bag to reinforce it. A fold over sewing bag sealer folds the top of the bag over and stitches it down. Some machines use single stitching, and some use double stitching. Products with bags that are sewn shut include bird seed, peanuts, and dog food.