Use Product Options drop down menu to select band size:
10mm belts are available for all Sanding Belt Attachments (on website now and/or since 2011) with serial numbers starting with the numbers 11 and higher.
Attachments with these serial numbers can use both the 7mm and the 10mm belts.
Attachments with serial numbers starting with 09 and lower can use only the 7mm belts. (The first letter of the serial number represents the month the unit was built and has no bearing on the belt width.)