They are readily available in the states. About $50 dollars so not cheap.
I bought one not so long ago for the Manzel on my roller via a friend who then posted it me as a gift so as to reduce the import taxes etc.
Part number 438-028-070 for current Manzel Model 25D lubricator.
https://www.graco.com/content/dam/gr...L51010EN-A.pdf
Joints for above also available, see parts list.