On the Card tap handle of mine it says in 3 lines "CARD, USA, #11". It measures 19-3/4" closed. I bought it about 5 years ago on ebay cheap to turn big NPT taps. I have tapped hundreds of 3/4 NPT fittings with this wrench. Edit: which i believe has a max opening of 1-1/8".
I believe the GTD equivalent to be a #7.