Zotto Sleep shawn took him up on the offer and they went to work experimenting with various formulas. They finally landed on a combination that found Shawn waking up without back pain, he loved it but there was just one problem – it slept hot. Really hot. We’re talking sauna hot! (Not surprising since memory foam mattresses had a reputation for sleeping hot.) So Shawn went back to the drawing board. Dozens of temperature regulating and phase-change materials were tested until they discovered a dual phase-change material that no only kept the mattress cool, it was actually capable of redistributing heat if the mattress became too cold. This was a technology not found anywhere on the market.