The Gorilla Grip ShelfGuard Liners for wire shelves are made from ultra thick polypropylene that?s built to last. These heavy duty plastic shelf liners for wire shelving create a smooth even surface that helps prevent small items from slipping through the cracks. Spill-proof waterproof and easy to clean Gorilla Grip?s ShelfGuard Shelf Liners are perfect for kitchens garages basements and more. Plus pre-cut curved corners ensure a seamless fit on most standard wire shelves making organization easier and more secure.