4mm plate foam, 2.75mm bottom foam custom cut to fit the Dimple keyboard.
If you don't know what a Dimple is, you're on the wrong product page and should ignore the header warning up at the top and go ahead and click away from this page now. Do it!
OK, if you're still here you know what to do next. Add this foam to your cart and continue shopping as if everything was OK and no one will know any different.
The case and PCB this foam was designed for can be found (if you are very lucky) at lazydesigners.cn