CHENGYIDA Knife Upper blade# 340406 Serger Pfaff 774 776 783 784 785 786 787 788 4760 Knife Upper blade# 340406 Serger Pfaff 774 776 783 784 785 786 787 788 4760 Guaranteed to fit J.C. Penny Serger Machine Models: 928 Guaranteed to fit Mammylock Serger Machine Models: ML1026, PL1026 Guaranteed to fit National Serger Machine Models: N30, N40, N50, N50E Guaranteed to fit Pfaff Serger Machine Models: 774, 776, 783, 784, 785, 786, 787, 788, 4760 Guaranteed to fit Supreme (Nelco) Serger Machine Models: S928D