My favorite shoulder sponge.
Simply the best cushion, for people who don't use shoulder rests. Just slip under your shirt. (it won't work as well however to attach it directly to the violin, because of its rough texture, and because it would mute the sound somewhat - so it's recommended for people who perform in shirts). Zukerman, Cho-Liang Lin, there are many people who perform with cushions in their shirts and no shoulder-rests - and this is a particularly good one as it won't move or slip around under the shirt, as it has a rough texture that makes it kind of sit in place.
If it's too thick, you can cut it, but it will eventually become too thin as it gets broken in - you can just do what I do: I put some books on top of it for a few months until it's softened up, before you use it. At that point it'll be the right height (I think the height when it's new is a bit too high for most people)