The machine adopts two straight needles,standard vertical-axis rotating hook with self-lubricating feature for catching thread loops and sliding can take-up to produce tow lines of double lockstitch,Synchro feeding of needle bar and feed dog assures even stitches and prevents materials being sewn from shifting.Knob-type stitch refulator and lever type reverse feeding mechanism permit convenient operation.The arm shaft and hook shaft are supported by ball bearinges with synchro tooth belt for driving and plunger available for stitching shirts,uniforms,overalls,women’s underwears,jeans,etc. HM60518-7 is large haook double needle sewing machine;HM60528 is separate needle bar double needle sewing machine.