Material: Our flap discs are made of high-quality resin-bonded alumina abrasive, which is durable and has good abrasion resistance, antistatic and anti-blocking. Size: Our flap disc set includes 10 pcs 60 grit and 10 pcs 120 grit with 4'' diameter and 5/8'' arbor size. Multifunction: The cut off wheel are suitable for metal, stone, wood and plastic which can be used for grinding, welding, deburring, rust cleaning and so on.