We purchased the Probreeze approx 2-3 yrs ago. Started with King split. That did not work. The beds kept moving apart. We then purchased a king. They said we could put the king mattress on the twin bases. Never should have agreed to that. The bases still move apart even though we have a king mattress on them. Our biggest issue is that one side of the king mattress is lower than the other side. No matter where I start out when I go to bed, I always end up on the outside edge. I have actually FALLEN OUT! I am wondering if it is from the twin bases being tied together making the center higher than it should be. No reason to comment on the cooling aspect . . . I have far more serious issues with trying to stay on the mattress!! We try to laugh about this mess but it is clearly not funny. Spent lots of $$$ on this bed and are so disappointed.