Roloc Quick Change Discs are also known as Type III rapid change fastening system. These Quick Change Discs are made from a versatile aluminum oxide abrasive grain that is tough, durable and provides an aggressive cutting action. These superior Quick Change Discs feature a heavyweight cotton backing for a dependable product that is great for grinding, blending and finishing. These discs have a "roll on/off" style fastener made of a hard plastic and must be used with a Type R (III) Mandrel. Try these Quick Change discs today to see how they increase productivity by reducing downtime between disc changes!