Air-Lock Winter Quilt is made of 95% high-warm Polish white goose down and the Labyrinth Seal Stitching Technology. It solves the problem of heat loss with traditional quilted duvet. The product uses a difference in size between the upper and lower quilt layers to prevent cold air get in and hot air get out through stitching lines, effectively keeping warm temperature. The lower layer of the quilt is designed with a large boxes and a low-curved surface to provide the closest fit with human bodies, provides close-body warmth for everyone.