Sack Ups Protector 12 Knife Holder AC. This knife holder by Sack Ups is silicone treated to prevent rust and to wick moisture away from your knives. The Sack Ups Twelve Knife Silicone Sack Protector will help keep your knives in pristine condition and looking new. Specifications for Sack Ups Protector 12 Knife Holder: Manufacturer: Sack Ups Closed Length: 5 in Package Contents: Sack Ups 12 Knife Silicone Sack Protector Sack Ups AC801: Protector 12 Knife Holder