Gator Waterproof Sanding SheetsGator waterproof sanding sheets are designed for applications where wet sanding is required. The paper backing is specially treated to maintain it's strength and shape even after being soaked in water for an extended period of time. The sharp, fast cutting silicon carbide grain works well on metal surfaces and between coats of paint, primers and sealers. Best for wet and dry sanding applications on metal and finishing between coats Waterproof paper