If down is not for you, consider our Dacron® down alternative duvet. To ensure that it is just as cozy as down, we developed a special blend that clusters, lofts, and compresses like the real thing. Plus, the alternative fiber echoes downs softness and adjustable insulation. It is also hypoallergenic.Dacron® is a brand of polyester used as down alternative fiberfill; fibers can be luxuriously fine and lofty like down itself, or firm and supportive for use in mattresses and mattress pads.400 Thread count sateen shell.