Wool is a natural insulator that helps regulate your body temperature promoting a better night's sleep. The factors that contribute to this are as follows:

An Insulator, Cushions & Comforts, Absorbent, Durable, Non-allergenic, Natural fire retardant and Naturally mildew and mould resistant.

Some Natural Rest® Beds use synthetics that mimics some of the wool properties, these are the same space age fillers used in the worlds finest sleeping bags.