The left feeding roller ensures the fabric and tooth are synchronous to convey smoothly.2 rectifying devices， control the body edge more sensitive and stable, ensure the overlapped stitch and seam allowance are consistent. Extend the suitable range for the regular radian unit. Fabric adaptability widely, different fabric colors can be switched easily. Infrared detection assists to locate the rear seam position accurately.Automatic seam inspection， can detect the seam position and start stitching even if the rubber band is placed arbitrarily. Automatic differential adjustment device to achieve uniform sewing effect. Highly automated, adjust simply, and operate easily.