Collet size question

What is the difference between ER11-A and just plain 'ol ER-11, or is there any. Just saw a good price for a variety of the ER-11’s o0n Amazon, but the specs on here says the 24vdc spindle I have uses the -A.

The difference between ER11, ER11A, ER11M is in the collet nut i.e diameter,thread,etc, , not the collet itself.

thanks, Geoff. After looking at more products on Amazon and the specs, I figured that’s what it was… You just confirmed it!