The 50mm x 1830mm (2" x 72") size is a common size for Knife Grinding machines.
Abrasive belt kits to enable the production of a quality finished knife, these can also be used for Woodworking tools.
These belt kits come in three sizes; Basic, Small and Medium, see below for details on the Medium Pack.
 
The Medium Pack 
A broader range of belts to enable production of a higher quality finished knife, contains the following belts;
  Grinding primary bevels prior to heat treatment:
    - 5 x P36 grit Ceramic belts 
    - 2 x P120 grit Ceramic belts
    - 1 x P200 grit 3M Trizact A100 Gator Belt 
  Finish primary bevels: 
    - 1 x P400 grit 3M Trizact A45 Gator Belt 
  To satin finish:
    - 1 x Fine Surface Conditioning belt
    - 1 x P400 grit 3M Trizact A45 Belt
    - 1 x P800 grit 3M Trizact A30 Belt
    - 1 x P1400 grit 3M Trizact A16 Belt
  Felt to polish:
    - 2 x Cleaning and polishing Belt