(I know its huge, hence the cut. I just wanted it to be very clear.
They seem to be some sort of very stretchy fabric, about the same thickness as denim, but much glossier and smooth. I really like these boots, they are ridiculously comfortable, but the zipper broke on one of them and I have to pin it closed now. I want to find another pair of the same material, but I don't know what to look for.