There is a steel filter under the big nut and the body is marked Apollo 400 cpm
Thanks in advance

That's a debris trap. It goes in a water line to catch any crap that might be in the water. It will be a very coarse filter screen so don't expect it to filter out bio hazards LOL.
We used them at work on all the machines. Industrial.
If you pull water from a well you would probably have one in the system. Used in applications where the water may not be the cleanest.

some of those type filters will also have a flapper valve that keeps it from back flushing the crap out of the screen.
looks like an antique yard stick you have there, I think all the ones my parents had were broken somehow :)

Also known as a "Y" strainer. We use them here also as a coarse filtration system for our paints and solvents for our aerosol fill lines.

Rand

I knew u guys would come through for me and I appreciate it.
Yeah I pulled out the antique yard stick with the big numbers. Lol.
I think more parents need to have broken yard sticks these days.
Thanks again all
Edd