PART#:H004254+H004131 THIS LISTING INCLUDES : 1SET BRAND NEW HIGH QUALITY Upper and Lower Knife Set . Fit for Elna Serger Machine Models: 744, 905DCX, 925DCX, 945, PRO4, PRO4DC, PRO4DE, PRO5DC, PRO5DE Fit for Pfaff Serger Machine Models: 4852 ,4872 ,Please pay attention to the size of the product !