... rotating hook & bobbin,suitable for thick thread stitching.2. Equipped with the strong & durable mechanism,suitable for stitching the bulky articles ... upper & lower sewn materials,ensured the perfect & fine seams.4.With light touch to the reversing lever,stitching can be reversed ... materials,such as tent,seating,buff, harness,jute bag,automobile top,water-proof cloth,bags,etc..