The Mercer Industries type 27 Semi-Flexible disc is made with silicon carbide grain and can be used wet or dry. It has a hard plastic back so No backing pad is needed. It features a spiral design which permits the disc to run Cool and prevents loading. Grinds aggressively on a variety of surfaces easily removing coatings, adhesives, paint and mastics from Stone, concrete, fiberglass, and non-ferrous metals. Use on an angle Grinder. Mercer Industries is a 3rd generation family owned Company that was built on core Values of quality, performance, delivery, service, and price. Founded in 1968, Mercer Industries offers more than 3, 000 products for the flooring, industrial, automotive and welding markets. Mercer is committed to serving its customers and providing quality products. For more information, visit mercerindustries dot com. Weâre here to support you. Please contact our team at info at mercerindustries dot com with questions or comments. Claims for warranty must be made within 90 days of the date of purchase. Proof of purchase required. This warranty does not cover any product that has been subject to misuse, neglect, negligence or accident, or that has been used in any way contrary to the Purpose intended.