Square Cut Rubber Drive Belts.
SC =Square Cut, The following letter refers to the cross section / thickness of belt.
SCY=.028"-.039" Wall Thickness, SCX=.040"-.049" Wall Thickness, SCQ =.050"-.064" Wall Thickness, SCA=.065"-.079" Wall Thickness, SCB=.080"-.094" Wall Thickness, SCC=.095"-.145" Wall Thickness.
The last numbers refers to the length of belt. This would be the circumference measured in inches. You can also cut the belt and layout on a ruler for measuring. (Note: not diameter)