PolyOpaque - A4 PolyOpaque Cover Material made from high-quality, recyclable polypropylene protects and enhances A4 documents permanently. The material features one smooth side and one slightly sand-structured side, available in various colors. It protects against stains and scratches, making it ideal for frequently used documents. Made from environmentally friendly, recyclable polypropylene. Strong: made from durable, 300-micron thick, waterproof polypropylene. PolyOpaque bindings protect your documents from stains and signs of wear. Available in DIN A4 and A5. Choose from 5 classic business colors: White, Black, Blue, Dark Red, and Dark Blue.