I found this tool no. 2166 use on part 35165. Can anyone help me identifying this tool?

Lock-ring tool?

Lock ring, or shaft seal pack nut, or tube lock ring.

It is open on the end so it can go around something almost as large as the nut...

The design is common for aircraft tool used for installing push rod tubes on open frame type aircraft engines...
Find nothing for the part number tho :(