It is for single needle flatbed machine, for suitable for common fabrics or leather. Size 9# to 16# suitable for embroidering or zigzag stitching on thin or medium heavy fabrics, like knitting goods, cotton textiles and chemical fiber. Size 11# to 18#, is suitable for sewing up gloves, camera cases, leatherette, toys, slippers, pillows and doll shoes, etc. Size 9#~14#, is good for Double needle zigzag chain stitch machine or Pin-point (bed-lack) machine, and it's suitable for sewing ornamental stitching trousers, children's wears and gloves. Size 19#~24# is suitable for sewing ultra heavy leather. Equivalent systems include: 1738; 287WH; 16X257; 16X231; 16X95; SY2254.