Optibelt VB S=C Plus Z section Z/10, 10mm = width across the top of the V

Classical V-belts, DIN 2215

Z/10 Section, Please note. Some of the smaller sizes will come with teeth on, flexibility for going around smaller pulleys.

The item description is what should be marked on an Optibelt belt. To explain its give the metric and imperial size.

So the Z31 means its 31" (inches inside length) 775Li is the inside length in metric. 797Ld is the datum length which is the length if you measure the middle of the belt all the way around.