NOT JUST CONNECTORS!
With a microfilter in the inlet fitting and a restrictor in the return fitting these can very easily get blocked as you can see from the picture above from a customer's Adblue module.
 change these and the AdBlue filter first when I have pressure faults. it allows me peace of mind that all the small internal passageways are clear and good 👍
Please note you are purchasing one set (3) items