The O-Wool™ mark represents the highest standard available for certified organic wool products. O-Wool™ sets the industry standard by distinguishing itself from other products made with wool and organic wool. -Wool™ yarns and fabrics are made only using wool certified by US Department of Agriculture-accredited organic certification agencies. In addition, the products are processed using the most sustainable methods commercially available. (sheep have dark and light coats so you may see some dark fibers with the light) Exclusively Pure-RestOur certified organic Pure-Rest O Wool puddle pads are made from a pure organic merino wool from healthy organically raised sheep making them the softest natural moisture protector on the planet. We do not clean ours with sulfuric acid, instead we use combing to retain the purity and yet provide a clean product. These pads are so soft and so easy to care for. Occasional machine washing is okay if needed. Airing is even better to retain the natural lanolin. Protect your mattress. Wool naturally repels wetness, dust mites, mold, and is a natural flame retardant. Hand or occasionally machine wash and hang dry. Keep in mind our wool pads do not need constant washing because wool does not harbor bacteria or mold. We recommend the organic cotton mattress pad for lots of added absorption protection.