I think it's called the "bathtub", it's the plastic (ABS) liner in the 210 wheel well. My questions are:
1. What year did Cessna get this bright idea?
2. Why is this fragile liner in there ?
3. I have searched the parts manual looking for a picture and part number, no joy?
4. is there other airplanes that have these liners?
Thanks. bk

I believe the “bathtub” came about when Cessna redesigned the gear without gear doors.
The object was to keep CO out of the cabin.
To find a part number look at serial numbers without gear doors from the factory.