Sack-Ups Knife Protector 5 5 Inch/6 Pak. Contains six silicone treated gray cotton pouches. Protects knives from rust, dirt and scratches. Will hold knives up to 5 inches closed. Hang packaged." Will hold knives up to 5" closed. Contains six silicone treated gray cotton pouches. Protects knives from rust, dirt and scratches. Hang packaged.