Arc Abrasives 31728 Type R Zirconia Alumina Quick-Look Discs measure 3 Inch in diameter. They feature Performance Coating, which alleviates heat from the grinding process so that excessive heat won't load the disc material with aluminum or other soft metals. These discs also have compact grains that have multiple layers of the same grit -- compared to only one layer of a conventional coated abrasive product. As an entire layer of abrasive grain is worn away, another layer is exposed. The compact grain construction results in less loading, longer life and a consistent finish. The small diameter of Quick-Look discs leaves a small grinding footprint and allows the user to grind or polish in a space where a larger tool would not reach. A smaller footprint also allows the grind lines to stay tight to the weld area creating less secondary finishing work. 50 Grit. Pack of 50 discs.