A a blend of Muscovy down and feather (which stick together and trap more air) this design provides excellent insulation and extra softness for a cloud-like weight that's light and comfortable to sleep under every night. This collection is cased in a luxurious 233-thread-count cotton cambric and has an internal box construction for even warmth (meaning no cooler patches) to keep you the ideal temperature all night.This duvet comes with buttonholes and cufflinks so you can build your own tog rating by joining two of the same range together during colder months.