The wrong size

But we like the shape of them. F thinks I make a necklace or earrings out of them. I've no idea what they proper name for them is, but F is looking for a 9mm one for his Canondale bicycle - he's been sent every other size except the 9mm. Apparently only Canondale make a 9mm one. The folk who gave the bicycle its service and who left off the part are going to track one down for him.