I did not know they made them. Are you sure they are made by CH and not for CH panels by some other manufacturer like Cutler Hammer? I know they makes lots of things for hazardous locations and conduit fittings etc. but not breakers?
I just visited crouse hinds web site and by coincidence one of their Hazardous location breaker enclosures use Cutler Hammer Breakers for 15 to 100 amps. The larger breakers are listed as FLB and I have no idea who makes those.
Siemens bought the Crouse-Hinds line from Cooper & restored the former Murray name when they did that, they dropped the Murray circuit breakers & rebadged the I-T-E design breakers they already were manufacturing.
Your best bet may be a electrical liquidator or other elect. surplus dealer.
Oooh, I remember those. Challenger made the same style with the cheesy little clip that's supposed to carry 30A. The clip is smaller than a Zinsco clip, and most of us smell $$$ when we hear a customer say "Zinsco"
When I ran across these I'd usually rework newer style twin/quad breakers in to make things happen due to the amount of failures I've seen with the clips.