... semi-rotary large capacity shuttle hook, suitable for sewing heavy weight materials. Used for harness, tack, saddlery, ... can sew accurately and easily several sheets of heavy weight materials piled up together.The lifting amount ... hook & bobbin, could reduce the frequency of changing the bobbin thread a built in bobbin winder, ... Arm, Cylinder-Bed, Unison-Feed, Extra Heavy Duty, Lockstitch Sewing Machine