2 pc Serger knife Upper and Lower Singer maintenance pack Brand New Upper and Lower Carbide Steel Blade Knifes (2 piece set) SERGER MAINTAINANCE PACK Durable, Accurate Angle Blades Ensure smooth sewing and professional cuts Singer 14SH644 , 14U part# 412585 and 412749 Includes lint brush and needles. Keep your serger well maintained.