when the second plastic one on the safari started showing 'age' at only (2) years after install
i found a powered coated steel one online thru a link on a Monaco Forum
that was in 2014 IIRC it $149
it did come with a site glass, although i had to move it to a spare 'hole' facing outside what was the rear of coach
I can explain it to you.
But I Can Not understand it for you !
....
Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s