This machine adopts two straight needles,vertical-axis roating hook with self-lubricating feature for catching thread loops and sliding cam takeup to produce two lines of double lockstitch,The needle bar can be engaged and disengaged mechanically and the arm shaft and hook shaft are supported by ball is provided with synchronous tooth belt for driving and plunger pump for lubricating ,and knob-type stitch regulator and levertype reverse feeding mechanism.The sew thread pulls back spring in the bobbin case and guarantees the harmony between surfuce thread and bottom thread,Besides it features synchronized feeding of needle bar and feed is recommended for stitching overalls,uniformsjeans and decorative sewing on bags.