I don't know much about them but they all should be about the same design.
The difference may be in the pressure ratings and what industry/applications they are used in.
I do know that Nuclear, Safety related grade for nitrogen are really high dollar.

Don

1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!