THESE SPECIAL BOLTS/ NUTS ARE TO FIT A M10 (9.9mm) CHAINRING AND HAVE A BEARING SHOULDER OF 16mm DEPTH. STEEL FINISH NUT (9.8mm nominal) FOR M10 HOLE WITH A 16mm SHOULDER DEPTH. THESE ATTACH THE CHAIN RINGS TO THE CRANK ( PEDAL ARM ) ON CHAIN WHEELS WITH DETACHABLE RINGS.
