These sheets can be used for wet or dry sanding, and are washable and reusable. Includes five sheets, 15 000, 20 000, 30 000, 40 000 & 60 000 grit, each measuring 4 x 4′ 10.1 x 10.1cm. WARNING: Drilling, sawing, sanding or machining wood products can expose you to wood dust, a substance known to the State of California to cause cancer. Avoid inhaling wood dust or use a dust mask or other safeguards for personal protection.