Maybe its this type of compression fitting? SelfAlign ? page 52
It is in this catalog https://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/pll_1015.pdf
Those have a higher rating then that. page 46
in this Quincy QT-54 manual https://www.aircompressorsdirect.com/manuals/quincy-016ebdd7885d7da9902daf96f8b3aba5.pdf its shows and numbers all the fittings expect the one painted blue
Hopefully something helpful here