SR-491 single needle drive roller thin post bed lockstitch sewing machine and  sewing more efficient, stitch more beautiful.adopts double idler wheels and needle feed materials at the same time, strong slope climbing foe ce, small change of needle. it can sew sponge, thin leather with even, smooth and inflexibility. it adopts ball and needle bearing with fine needle bearing with fine lubrication ,little attrition , low noise and long life, thin leather with even, smooth and inflexibility. it adopts ball and neddle bearing with fine lubrication ,little attrition, little attrition, low noise and long life. suitable for sewing riding boot, gym shoes, leisure, spong shoes,baby's shoes, high gread leather shoes and all kings of cases