When my friend got his Alto, he also looked at the protec cases at Guitar Center. He got the most wonderful case for his Alto. It has very plush, thick fabric all over the inside, much plusher and thicker than the felt in other cases I have seen. The “fur” is about 1″ deep if you draw it out, and the horn sinks into it..
The case is not totally open and empty inside with a notch for the end of the horn to fit into and a small partition for stuff like most cases. You open the case and the surface that the fabric is on is flush with the opening of the case. There is a part where the shape of a saxophone has been indented into it, which holds the horn snugly on all sides, but underneath the thick furry soft stuff it is not hard. It has an amount of give or springiness that almost feels like that padding that you put underneath carpet. Of course, if you push hard enough you will hit something underneath. It almost feels like it was carved out of a solid piece of wood, but it’s way too light.