Quick Change Discs Set - 40Pcs Aluminum Oxide discs, 5 kinds of common grits (36/60/80/120/240) to meet your various grinding requirements, each kind has 8 Pcs; The Quick Change Sanding Discs can meet the requirement of 23000Max. Rpm. Material - The Quick Change Sanding Discs made of Premium Alumina has high abrasion resistance and hardness, and the is attached with thermal and blocking coating, which can improve the grinding efficiency and service life. Quick Change - These quick change disc has safety torque screw, the connection between sanding disc and rubber holder get firmly when rotating, ensures steady working and no fall out. Just twist it to remove or connect, convenient and efficient. Wide Applications - Various conditioning discs are excellent for using on surfaces of carbon steel, stainless steel, alloys, iron, non-ferrous and other nonmetal materials like wood, glass, ceramics, stone. Wide used in shipbuilding, car building, aviation, machinery. size: 50mm Material: Alumina colour: As shown Package Contents: 40 x sanding discs 1 x sanding disc 2 x conversion heads Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.