Peli 1500D Desiccant Silica Gel

It is compact and appears to be robust. It fits nicely under a short lens, with a piece of foam in between, in my Flyht camera case.
It is neat that it has a window through which you can see a colour change when it needs to be rejuvinated, which is 3 hours in a low oven. I anticipate it will have a long life and save both time and money.
The only downside is that the bottom edges are a little sharp, but as I put a losely fitting piece of foam over it, that is not a real issue.