A hidden sewing machine is a specialized sewing equipment that uses a single curved needle and a single chain stitch. Suitable for various fabrics such as cotton, linen, and floral fibers, including the viewport, pant corner, glove tube edge, sock tube edge, and other areas. Use a single line chain to pry and sew the edge marks.

The 500 type concealed sewing machine is equipped with a skip stitch device, which can sew general pry edge marks or skip stitch pry edge marks.