I really don't know! It's about 2.5" in diameter and it is covered
with a
ubber seal. I put a bit of grease into it every couple of years, and
it
doesn't leak. A few years ago it dripped for a while.


Dripless seal as on my boat. Both surveyors called it very reliable and
told me not to mess with it. My bilges are dry and clean...I mean
snow-white clean!

RB
35s5
NY