Avery 72611 Heavy-Duty Plastic Sleeves, Letter, Polypropylene, Clear (Pack of 12) Reusable heavyweight sleeves are perfect for projects and organizing office space. Clear folder allows you to view contents easily. Sealed on two sides to hold items securely. Non-stick, polypropylene material won't lift print. Sleeves hold up to 20 sheets of 8 1/2 x 11 paper.