The 50mm x 2000mm (2" x 79") belt is a common size for Knife Belt Grinding machines. 
 
3M 337DC Trizact  is a 3M Specialty "Structured" abrasive that is ideal for fine finishing
Macroreplicated abrasive "bricks" contain multiple layers of abrasive mineral, "channels" keep remove swarf and keep work surfaces cleaner
Controlled mineral breakdown delivers more consistent, predictable finishes over the life of the belt
Durable cloth belt is frequently able to grind and finish in one operation
Grinding aid reduces friction and keeps workpiece cool for dry grinding applications
Designed to save production time with fresh cutting surfaces continually exposed, resulting in extended belt life, reducing frequency of belt changes
 
The price shown is per belt.