Nylon backed cloth belt that is used for polishing metals.
It is recommended to load the belt with a diamond/CBN emulsion or paste, or alternatively, you can use green jewellers rouge

Run at approximately 2000sfpm for best performance.
Store in a Ziploc bag to keep the belt free from contaminants.
These belts can be expected to last up to a year from heavy knife sharpening use.

Stropping Belt