Cushion between the cabover and Truck

Hi all. Just bought my first cabover( along with the a F-250 already set up to the specific camper). I am very eager to get out in the camper, but I also know there is a large learning curve I need to over come.

I am currently on the hunt for some items and I don't know what they are called. I refer to them as doughnuts. One goes between the slider in the truck cab and the slider in the camper to allow you to pass things through.

The other is similar but larger. It sits under between the camper and the top of the truck cab to cushion any contact that may occur between the two and provide additional support to the camper.

I searched here, but not knowing what these are called makes searching for them a challenge.

Can anyone recommend solid, quality products that fit the above descriptions please?

Thanks!