FantastiCAR Soft Material Grip Retractable Utility Knife, Snap-off Safety Box Cutter, with Extra 10 Blades (18mm) , and Can Opener Design, for Heavy Duty Work, Carpet, Cartons and Cardboard (Black) - - Amazon.com
Tape King Utility Knife Box Cutters (12-Pack Bulk, 18mm Wide Blade Cutter) - Retractable, Compact, Extended Use for Heavy Duty Office, Home, Arts Crafts, Hobby for Cutting Boxes, Cartons, Cardboard - - Amazon.com
TOPLINE 2-Pack Utility Knife, Retractable Box Cutter and Folding Pocket Knife, Blade Storage Design, 18-Piece SK5 Blades and a Dispenser Included (Yellow) - - Amazon.com