Resealable Plastic Wrap Cardboard/Slim Poly Sleeves. Sleeve color: clear. Made from oriented polypropylene (OPP) material, which allows for a flexible and protective sleeve. For easier insertion, the resealable strip is located on the body of the sleeve, not the flap.Thickness: 30 microns / 1.2 mil.Designed to hold cardboard sleeves, resleeves and slim poly cases.