Collets types question ??

[graham-xrf]

I have the set of ER32 collets with MT3 collet chuck.
Looking at other sizes, like ER11 and ER16, I see a designation that has gained an "A"
What exactly are "ER16A" collets?

 

[T Bredehoft]

It seems to have something to do with inserting and removing the collet from the nut. Perhaps an improvement, perhaps a marketing ploy.

 

[Jake M]

My understanding is that the letter has to do with the design of the nut. Hook wrench, pin wrench, hex wrench, and I think there were coarse and fine threads thrown in there too.