This series interlock sewing machine is a big group. It can apply various accessories to perform many functional stitches. It is a necessory machinery for a mass products of garments and it is widely used in stretch sewing of fashions, materials such as underwear, T-shirts, shorts and knitted fashions, knitted coats and jeans etc. It is also applied for functional stitches like hem collar bound seaming, elastic arched stitches, fancy stitches etc.