here's a handy little chart on ferrule sizes for those who are confused about how the sizing system works, as you can see below all ferrule sizes are measured by "pipe" size and "not" the ferrule face.
Hope this helps :handgestures-thumbupleft:
Please not that "A" in the chart @ 21.5mm is what we stock as standard items, we can usually get the other lengths in around 21 days if required.
Cheers.