3M SandBlaster Angle Grinder Multi Layer Discs are a part of a unique Quick Loading System for angle grinders. The Quick Loading allows a variety of versatile grinding, sanding and finishing discs to be attached quickly and easily without the need for wrenches. 3M SandBlaster angle grinder multi layer discs can be used on many surfaces, including metal, wood, and fiberglass. They are made with a durable Cubitron mineral, resulting in less burning and a longer disc life. In addition, as the multi layer disc is used, fresh abrasive is exposed as the product wears, enabling simultaneous material removal and finishing in one step.