Polypropylene cover filled with anti bacterial treated polyester hollowfibre which protect against dust mites. Homedream Mattress Protector Features: Anti bacterial Fitted skirt Washable Cover: Polypropylene Filling: Polyester hollowfibre Available in: Double - King - Single 4.49 5 DL D False Bedding 5.99 5.99 Homedream Anti Allergy Mattress Protector | Kaleidoscope