As seen on tractors up and down the country, this steel seat pan is cushioned with foam and then covered in a vinyl trim, it also has 3 drain holes to allow water to run off.
There are 2 studs on the base of the seat, these are around 2″ apart and this type of seat would usually be fitted onto a seat spring and the studs would pass through the spring and be bolted underneath.
This seat can be used on many older tractors that had this type of seat for example the Ferguson TE20, various David Browns, Allis Chalmers etc