Adopted with big hook and bobbin can save the time of changing the base thread to improve the efficiency of sewing. Walking foot, needle feed, and feed dog makes the unison feed, which can sew easily several sheets of heavyweight materials piled up together and makes accurate and uniform stitch even on materials with rough, slipper or tacky surfaces. The length of sewing can be adjusted easily and with a light touch to the lever, stitching can be reversed. Auto lubrication system makes smooth and noiseless running when it operates, it's easy to maintain.