Hi Ricool,
The Duo uses organic Dunlop latex layers (which as you can see here would have the same “feel” and performance as 100% natural Dunlop of the same type and firmness level or density but didn’t have an organic certification) so you can use that as a reference point in your conversation with SleepEz (or any of the other online manufacturers that are members here that supply similar component latex mattresses online at a significantly lower cost).
If the organic certification of the materials is important to you then some of them also sell GOLS certified organic Dunlop latex and organic cotton and wool covers so the only real difference would be any differences in design and that their factory doesn’t have an organic certification.
Phoenix