The 5" Royal-Cloud pillowtop pad (it is also available in 4") contains a layer of natural latex (a resilient, more supportive, and heat absorbing alternative to memory foam). The latex is encased in 100 percent Belgian cotton fabric covering; untreated New Zealand lamb's wool; and hypoallergenic Comfort Fil 7. It is a perfect complement to many firm mattresses, and contains three times as much latex as the more economical 3" Royal-Pedic pillowtop pad.