The Standard Abrasives 522352 Quick Change Disc features a 1-1/2" diameter with 36 grit aluminum oxide abrasive material for extra coarse sanding. The disc backing material is cloth, and it is coated with abrasive type for efficient metalworking. The disc attachment system utilizes a TS/TSM Turn-On/Off mechanism for easy and secure attachment, making it ideal for CNC and metalworking applications. This 50-pack of quick change discs offers high-quality and reliable performance for various industrial sanding projects.