roof exhaust

i like the idea of the spring cap, temp fix while its so hot outside.

also what about under the sink vent anyone have issue with these?

I'm not sure the formal name but I walked into an RV dealer and told the man "I need a hat for the Stink Pipe" and ... He took me directly to it, no ambugity at all, he led me directly to the display..

Suggestion.. Consider one of the advanced units like the RV 360 sanitation vent
Click here for a page of them on Amazon

I use a different advanced model on the black tank.. These look,,, interesting though.

Could be either of the above depending on if it is a plumbing vent, or an attic vent. Attic vent is much wider diameter than a plumbing vent.

I just replaced two attic vents (second link above). They were not missing or broken, but were beginning to get chalky and brittle. You can just screw the cap off the new on and screw it on the old base and not have to worry about trying to get the old base and caulking off.

If you are missing a plumbing vent and the base is still intact, the easiest thing is to replace it with a spring loaded cap like this one. I lost one to a tree limb and it broke part of the base. I installed one of these as a temporary measure until I could replace the base. That was several years ago and it is still there. :)

Does it screw onto a stud? Does it look like this: Mushroom vent cap?

You probably just need to get something like this to fix it:
Vent cap assembly

How big is the missing cap?

probably a vent cap