... hook, suitable for sewing heavy weight materials. Used for harness, tack, saddlery, canvas, sport equipment, footwear. Such products ... frequency of changing the bobbin thread a built in bobbin winder, which can be reached with ... ease during sewing.The machine incorporates a built in bobbin winder, which can be reached with ... Arm, Cylinder-Bed, Unison-Feed, Extra Heavy Duty, Lockstitch Sewing Machine