Our raw silk duvets are made from the highest-grade, long-strand Mulberry silk. Less expensive silk duvets usually do not include duvet covers like ours do. Plus, they may contain less silk by weight and lower-quality silk such as "broken silk." Whereas KAILU raw silk is naturally white and stretched into layers, "broken silk" is brown in color, has a clumpy texture, and cannot be stretched into the same layers that make our raw silk duvets so smooth and luxurious.