Check the listing for details. 25 Pack 3" 36 Grit Aluminum Oxide Roll Lock Die Grinder Sanding Discs US. Color: Red, Condition: New, Made in United States. Listed at 11.79 USD. Feature:SATC A/O Roll Lock Sanding Disc features an aluminum oxide abrasive, which is a popular choice among industrial professionals because of its cut-rate and long life. This mineral makes a tough, durable abrasive that self-fractures to expose fresh cutting edges, whereas traditional natural abrasives dull more quickly. Aluminum oxide is suitable for a wide variety of materials in both woodworking and metalworking, including ferrous alloys. Heat-resistant resin is a sturdy binding agent that adheres the abrasive to the backing and maintains the stability of the bond even in conditions of high heat or pressure. Cloth-backed discs are known for their durability and flexibility. The greatest advantage of SATC A/O Roll Lock Sanding Disc i.