Cubitron belt is said to have the "best life and performance". Cubitron cuts faster and cooler with the added bonus of lasting much longer then conventional zirconia & ceramic belts. Aggressive grind. 36 Grit.
Ceramic (Red) has a longer life for grinding metal than aluminum oxide or zirconia belts. An aggressive grind, commonly used for grinding shoes. 40 Grit
Zirconia (Green) is a particulate material that lasts longer than aluminum oxide belts. These belts have a 3M coolant coating on them. 40 Grit for aggressive grinds, 80 Grit for mid-range grinding, and 100 Grit for tool polishing/finishing.
Aluminum Oxide is often used for tool maintenance, finishing, and polishing. 180 grit or 220 grit.