To Fit Raytech Expanding Sanding Drums
About "Compact Grain" Belts - Aluminum Oxide Belts in super-fine grit (like 600) are only available in what the maker calls "Compact Grain". This process layers grit in a special adhesive and greatly increases belt life. Compact grain belts are easily identified; they are ugly! The 600 grit belt shown looks like it should be a 60 grit but IT ISN'T. It really will give a 600 grit finish and will last extremely well. Resin bonded, aluminum oxide. Sold singly.
Big Book Catalog, Issue:73, Page:399
Big Book Catalog, Issue:73, Page:430