Georgetown pottery make different sizes, at little pricey but it will keep lather warm. It comes with a cap for hole, I enjoy it.
Once I bought my Georgetown G20 I have not shaved without a scuttle. The SRD scuttle is great for keeping a brush warm but the G20 keeps the brush warm and let's you lather in it
I tended to use mine in the winter months, but when I got a Hot Pot for shaving uses only the Feats of Clay scuttle is now in storage (which I will hold on to for some time to come.)
I've had one for a few months and I enjoy it. Sometimes I get nice warm lather and sometimes no so much. I haven't figured out a reliable pattern yet.