I have to ask just what role this thing might play in a pump mechanism because there is no possible way anything can flow thru it; nothing attaches to it except that the head evidently can be changed.
The head can be easily removed by rotating it 90º and looks to me like another head, presumably with a different angle, can be easily substituted. The circumferential grooves in the supporting conical end suggest great force applied when in use. The wrench size (1-1/8") also implies great force.
The entire thing is steel except the head which is non-magnetic and might be beryllium-copper (just a guess). The vertical marks on the head suggest to me great force applied and if it actually is Be-CU that would make sense as that is tough stuff.
I think the whole thing is slipped into a holder of some sort then run up against something that needs to be centered but for what reason I cannot imagine.
Wow! did I write all that?
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Late note last reply while I was typing - the thing is 1-1/4 Dia by 7" long but can be adjusted to about 10" long. Weighs about 2 lbs.