Tuber Transportation

I am interested in mailing a friend some Hopniss(Apios americana) tubers and I am curious as to what steps I should take to ensure they arrive safe and sound?

If it matters, I am only mailing within the continental US.

There isn’t much to worry about with that species if they are still dormant. They are not going to freeze, so you just need to make sure that they don’t get crushed.