Using the fourth-generation servo stepping drive technology: Stitch accurate, motor temperature stable, quick reaction. Thread breaking sensor: When the thread is broken, the sewing operation will stop automatically and alarm prompt. The maximum speed is 2800rpm.: Comaring the normal pattern sewing machine, the proudction is 19%more. Low consumption and energy saving: Using drive, energy-saving 50% energy. The upper cover electronic winder starts working after turning on instead of winding during sewing in traditional way.