As the OP said, 3.75โ ID is going to be pretty tight with some couplers, and too small for many. I donโt think the previous responders realize that 3.75โ is NOT the same as the 4.00โ bumper they may have. I had one of those smaller bumpers on a previous camper, and I had to be very picky about which sewer hose couplers I bought.
These Valtera couplers may fit, though the outside diameter of the bayonet coupler is exactly 3.75โ. I like them because you donโt have to use a hose clamp on them.
Valterra F02-3101
Valterra F02-3102
Any of the RV sewer hoses that donโt come with fittings on them will likely work in your bumper, but I like this one.
:):)
2001 Lance 1121 on a 2016 F450 โScuse me while I whinge.
And for all you Scooby-Doo and Yosemite Sam typesโฆโฆโฆ..Letโs Go Brandon!!!