Steering Column O-ring Specs?

[mopowers]

Does anyone happen to know the size or dimensions of the large-ish o-ring that snugs up the steering column to the firewall? I realize DMT and others sell them, but if I knew the size, I can pick one up locally and not have to wait for shipping. Thanks!

 

[mopowers]

Anyone have one of these sitting on your bench that you wouldn't mind measuring for me? Thank you.