What kind of a/c line is this and are there replacements?

I yoinked this picture from an eBay listing https://imgur.com/MGc9WWR and hesitate on buying it because I don't know if its an exact fit or if it has its own problems but it's pretty much identical to the one in my 88, difference mine has a hex nut instead of this round one on the top end. Anyways I'm fixing the a/c and mine has a tiny hole/crack on the bung thing that spews out all the refrigerant I put into it so I tried JB welding it and either I didn't do a good enough job or it just couldn't handle it because it still leaked. So I was wondering what is it called exactly so I could find a universal version or something.