Box Cutter Retractable Utility Knife 4-Pack Heavy Duty Utility Knives With 10 SK5 Steel Blades Aluminum Casing Box CuttersBox Cutter Retractable Utility Knife 4 Pack Heavy Duty Utility Knives With 10 SK5 Steel Blades Aluminum Casing Box Cutters EASILY OPEN YOUR BOXES: VICRING heavy duty utility knife adopts SK5 steel blade, which is super sharp and double hardness. Easy to open and cut packaging boxes, cardboard, carpet, rope, rubber, leather, PVC materials, DIY, etc. FIND THE BOX CUTTER QUICKLY: 4 bright colors make this cute box cutter knife easier to find when stuck