This Anti-Allergy duvet by Slumberdown inhibits dust mites, bacteria and fungus so it's a suitable for allergy sufferers and all year round use. All Slumberdown Anti Allergy products come with Allergy UK's Seal of approval, which is only awarded to products that have been tested and approved to very high standards by leading allergy specialists. Slumberdown Anti Allergy 13.5 Tog Winter Duvet in White Size: King