In open stitched duvets (Karo-Step), the filling can move inside the duvet. The Karo Step stitched Duvet, performs the maximum loft and cozy warmth. The Karo Step Duvets doesn’t have any cold spots because the stitching pattern, which tacks the front of the shell to the back, can prevent loss of insulation by keeping the down from shifting. A Karo Step design, which gives the appearance of random puckering, is considered excellent for warmth by providing plenty of room for the down to trap air. The Karo Step Duvet, with its open-sided stitches allows you also to fluff down evenly or concentrate it where you want more warmth. It represents the classic European pattern with a lofty, plush look.

warmth scale 

Mussner Duvet Storage Bag

All Mussner duvets, blankets and comforters are delivered with its excellent soft Mussner Storage Bag. Due to the shear size of duvets they can be quite a difficult item to store. The Mussner bag is the perfect way to store and protect comforters, blankets and pillows. This protective storage bag is made of breathable denier fabric to keep out dust and prevent musty smells. This extra large storage bag is ideal for any trips, or for someone who likes to travel with familiar bedding. When it's time to store bedding this bag is the best solution. Never use plastic or nylon bags to store a Mussner Duvet.