20" front wheel in the unusual 440mm / 438mm diameter size (rim is marked 440mm but has a type marked 438mm which fits perfectly fine). The size is sometimes referred to as 20 x 1 3/8".
It is from a 1990s recumbent and am selling because I swapped the front wheel for one with a hub dynamo that I had made with a 451 rim. I've never seen another rim or wheel for size of this size so I would suggest it is most likely to be useful as a spare for a bike with the same rim size.
The hub is very smooth and while there is some rim wear it isn't bad and there is plenty of life left. The tyre has some cracking in the sidewall so isn't perfect but has a good bit of life left. Tube is fine. The rim is a nice quality eyeletted one.
I am selling a couple of new tyres of the right size in a separate auction.