I'm a fan of Scandinavian design, and something I see is a thinnish mattress on top of a zero-profile flexible slat foundation. I wonder what the "specs" are on these mattresses? I.e. what densities of foam are typical?

When I do Google searches, I rarely get hits outside the U.S. That may be a configuration setting I can change, in order to widen my scope.

I did manage to find a few U.K. mattress websites. Solid core 5.6" mattresses are not uncommon. They also offer thicker mattresses of course, but generally speaking, their mattresses are thinner than ours.

A flexible slat mattress works best with a firm thin mattress. Since slat foundations comprise 70% to 80% of the European market, it's clear that the foundation is considered as integral a part of a foam mattress "system" as it is with an innerspring mattress. We (Americans) tend to think in terms of rigid foundation and then a thick mattress, but I'm really wondering if the Europeans aren't a step ahead of us here. Smart design vs. brute force solutions.

As far as firmness goes, the mattresses seem to be centered around 36 ILD, pretty much as mattresses are here.

It's hard to know all of this for sure because I only found a smattering of websites, so I don't know if I got a true picture of "the European market" or whether I only touched the tail of the elephant.

On a rigid base, I can bottom out an ILD 38 talalay latex core, AND it doesn't not feel supportive enough. Over a flexible slat foundation, the character of the latex core changes completely - it feels supportive (because of the adjustable nature of the flexible slat foundation), and there is no bottoming out feel.