GB4-1 model is used to sew canvas, container bags, belts, leather, tent, luggage & thick material. Model GB4- ... lockstitch sewing machine, FGB4-1 model is used to sew canvas, container bags, belts, leather, tent, luggage & thick material. Up-and ... noise, ensuring the quality of the whole machine and prolonging service life. Oversize oscillating shuttle may be used to increase thread ...