The 100mm x 915mm (4" x 36") belt is a common size for Belt Sanding machines such as Clarke, Sealey, Axminster, Scheppach etc. as well as the more versatile 100mm wide Multitool MTA-364.
 
 
 
Aluminium oxide is the most common abrasive mineral and is widely used throughout the finishing industry. It is probably known as the least expensive abrasive and can be used on various applications, especially in the finer grit ranges.
 
 
 
The price shown is per belt.