BeerGrylls,
Here's a photo of the HX (scale is in inches).
...and here's another photo (scale is in inches)...
There is a sticker on the HX that says
KOAX CORP. - OKC (I think "OKC" means Oklahoma City, Oklahoma, USA)
And it also says;
KOAX P/N: 70310901
And also:
MAX WORKING PRES. REFRIG 500 PSIG 3447 KPA
And I weighed it and it comes out to about 5 pounds.
What I can tell you is that the guy I bought it from said it was "good for 1 Ton", but I have not tested or verified that.
From the information on the sticker, you ought to be able to locate official specifications on the Internet.
I can tell you that the original "dust caps" are still in place on the HX and it has never been brazed, never been put into service.
I'll sell it to you for $50 US, and the shipping cost would be additional.
If you need additional info, please ask...
Best,
-AC