A 2.5mm diameter 'O' ring with an internal diameter of 30mm. Made from Nitrile (NBR N70) rubber which is ideal for use as a drive belt on our wooden, plastic and aluminium 'V' pulleys. Suitable for use up to 70 Deg C.
Common practice is to slice the belt to length with a sharp knife ensuring the cuts are at 90 degrees and then glue using a cyanoacrylate adhesive (superglue). There is some stretch in the belts depending on the length but not too much.