Synchronous car also called synchronous machine, it is divided into two kinds of three synchronization and two synchronization.

Three synchronous machine, also known as integrated feeding machine, it is to point to by presser foot (small presser foot, feed dog and needle feed at the same time

Two synchronous machine, it is to point to by the presser foot (big presser foot, feed dog feed at the same time.

Three synchronous thicker than the two synchronous should eat more, presser foot is not universal, the shape is different.

Three synchronous sewing machine sewing speed than ordinary and two synchronous speed of sewing machine, sewing cloth also relatively smooth, the price is a little higher. If it is to do thick sewing machine sewing suggested three synchronization.