Smartsilk is the only all natural bedding to be certified asthma and allergy friendly by the Asthma and Allergy Foundation of America and the Asthma Society of Canada. Smartsilk is proven to be an effective barrier against dust mites, allergens and pet dander and is resistant to mold and mildew. Our Smartsilk silk filled duvet has a 233 thread count 100-percent cotton outer shell, is filled with 100-percent SmartSilk silk fill and is machine washable in cold water and dryable on low. Smartsilks 4 season duvet helps to regulate body temperature, keeping you warm in winter and cool in the summer. SmartSilk is scientifically proven to wick away moisture thus promoting a more comfortable nights sleep especially for those suffering with night sweats.