HONEYSEW Lower Serger Knife For Elna PRO4 PRO4DC PRO4DE PRO5DC Pfaff 4872#H004137 Serger Lower Knife Blade Pfaff Overlocker 4842, 4852, 4872, 4874 #H004137 Lower Knife Blade ELNA 604E, 624DSE, 644, 704DEX, 745,904DCX,PRO4,PRO5 #H004137