There were two rolls to try and both did the job. First was an exercise roll cut so it tapered down and the second a layer of foam around a cardboard tube.
The exercise roll was the better of the two for me , the tube with foam seemed to have no give in it at all. If the exercise roll was on the course next time out I would prefer to use it rather than my shooting seat.
It offered ample support and only supported my ankle not my thigh or aRse.