... needles, self-lubricating vertical-axis rotating hook for catch thread loops and sliding can thread take ... -lubricating can produce two lines of lockstitch, serve for the purpose of sewing shirts, uniforms, jeans, overcoats ... slippage and puckering between layers of materials, suitable for stitching shirt, uniforms, underwear and jean, etc ... DY-842A-003 high-speed double needle lockstitch sewing machine