This Slumberdown Anti Allergy Combi 13.5 Tog (9 + 4.5 Tog) Duvet is made up of two separate duvets that conveniently fasten together and come apart, depending on your needs. Use the lightweight 4.5 tog duvet for keeping cool on warm summer nights, or use the 9 tog duvet during transitional months when you require a more versatile, mid-weight duvet. You then have the option to combine the two, using the simple and secure press-stud fastenings, to create a super snuggly 13.5 tog winter duvet to ensure you stay warm and toasty the coldest of nights. The Anti Allergy duvet is specifically made with an anti allergy filling to help reduce the build up of dust mites, bacteria and fungus. Tested and approved by leading experts at Allergy UK, it's an ideal choice for allergy sufferers and all year round use. Our lovely and snuggly hollowfibre filling is soft and comfortable, and the luxury microfibre cover feels wonderful to snuggle up into - it gently wraps around your body so you can be cosy and still move freely through the night.