Portuguese Extra Super Fine Cork Rings
Custom Fly Rod Crafters has a very good stock level of 'Extra Super Fine' cork rings. These are the very best we can find and as you are aware there are many 'Flor Plus', 'Super-Duper', 'Mom's Very Best' rings out there but they are not what is described.
CFRC's description is what we do, we take the extra time to select the very best rings. We use these rings on our custom builds and rarely do we even consider filling. Yes, they cost more but there is less work for the rod builder and when you consider the overall cost of your custom build, the cork rings which we consider a major component, don't add much to the final cost.
Do yourself a favor, your next custom build deserves the very best cork!