In article ,
Don Foreman wrote:

The groove is deep. The O-ring projects only a few thou proud of the
plug, just enough to effect a seal. About the only way to get that O
ring out of there would be with a pick.

Also, if the kid did manage to get it out - it's rather difficult to
actually choke on an o-ring - it has a rather large hole in it (as do
most toys labeled for the under-3 set that can possibly be crammed in a
mouth.) You can gag, but you won't choke, as you can still breathe
through the hole. If swallowed, it will come out the other end, more or
less uneventfully.

Good going Don.

--
Cats, coffee, chocolate...vices to live by