Duvet is a soft quilt filled with synthetic fibre used instead of a upper sheet or blanket. Most Duvet Covers require a Duvet Cover. Comforters are quilted with a slightly thinner sheet of synthetic fibre and warmer than a sheet. Comforters can be used standalone without a covering. RAZAI is a quilt very similarto, if not a type of, duvet or comforter and it is called so in the Indian sub- continent.