Sayyes Box Cutter, 2-Pack Retractable Utility Knives With 10 SK5 Blades | Durable Aluminum Box CutterSayyes Box Cutter, 2 Pack Retractable Utility Knives With 10 SK5 Blades Durable Aluminum Box Cutter The Sayyes utility knife can do much more than cut boxes or packing tape. Better performing blades mean you don't need to save a lot of blades to change them. SK5 heat treated steel blades maintain sharpness for a long time. Strong and durable aluminum housing offers a strong grip when doing heavy duty work. Comes with extra 10 pieces sk5 steel blades.