I found all sizes from West Marine except the 1/2 inch diameter and the next smaller size (7/16 I think). I could find no US supplier for those two sizes. I too had to order it from Amel. I bought about three sets each since the shipping was more than the cost of the items. At one point I purchased some from Laurent in Guadeloupe.
The stuff I bought in the US seems to be of better quality plastic since it doesn't seem to crumble as quickly as do the larger diameters from Amel.
