Machine Washable Wool Mattress Protectors. This amazing new Wool has been specially milled by a new European process to make it completely machine washable (and dryable) without shrinking. Typical wool pads need to be drycleaned, or at best hand washed. St. Dormeir protectors have all the convenience of polyester fills, but you can now sleep on natural wool with all its famous characteristics. Breathability keeps you cool in the summer, and cozy in the winter, and it lasts years longer than polyester. Wool is even naturally flame retardant (Polyester burns easily because it is made from hydrocarbons - just like other plastics, gasoline, etc.). St.Dormeir Protectors are made with 100% Cotton Terry covers, filled with New Zealand Wool. This Cotton Terry is also used as the skirt that goes all around the sides of the protector, to fit completely over your mattress. It has full elastic all around the bottom edge for the best fit. They are extremely moisture-absorbant, and they are also very soft to sleep on.