There used to be a non-ported turkey choke that was marketed by Truglo called a Gobble Stopper but I thought it had a .665 e.d. in the Rem-Choke thread version. It may however have had a .655 e.d.
As far as I know, all Truglo chokes have been made from hardened steel and are rated for all lead and tungsten-based shot. The earlier Bansner chokes were made from that kind of steel as well.
I can't tell you much if anything else about that choke tube. The folks at Truglo could probably answer any specific questions about it.
That was the reason I asked the question.
Thanks,
Clark