3M Roloc disc 963G provides a quick attachment and features 3M's highest-performing ceramic abrasive grain on a durable polyester blend backing for outstanding durability and cutting efficiency on carbon steel and tool steels. The 963G disc offers significant productivity gains for applications such as rapid stock removal, grinding, blending and deburring on steel. - 3M Disc button color/grade chart Roloc discs provide a fast, efficient method for grinding, blending, leveling and finishing on all types of metal. They lock securely in place with just a half twist, another half twist and they're off. Each disc is color-coded by grade.