Also note that these quill seatposts usually have wedge binder designs that exerts a more distributed outward load to the seat tube, compared to a typical wedge design on a quill stem. This is to avoid bulging out the seat tube which has thinner walls than the typical steerer tube that stems are inserted into.
This Atax post in the pics from the OP is a cool design at the wedge area, but seems to be a bit over-built and heavy at the clamp.
Maybe it would work also best with an MTB that will require a stronger seatpost with best anchorage to the frame to keep the post from slipping when cycling on rough terrain....
Mid 80's Peugeot PSVN and PGN owners are usually looking out for these as the Delrin material at the clamp, sometimes crack apart and spare parts are almost impossible to find. They also sometime have these seize in the seat tube where the lower, separate parts of the wedge system gets stuck in the tube because of corrosion and he only way to get the parts out is with destructive methods.

Chombi