1. A unique cam motion take up lever with an oscillating shuttle and lock stitch facility. 2.length of stitch can be varied according to specific requirements. 3.quick and smooth operation. 4.control for forward and reverse stitching over bulky seams and joints. 5.1250 stitches per minute when operated on treadle. 6.auto tripping, spring loaded. 7.also available with open type shuttle race design that provides easy servicing and cleaning of dust.