Understanding Fillings Synthetic Man-made fibres ensure that the duvet is lighter, softer yet comfortable giving the same warmth for less weight. They are also a practical choice if you are allergic or sensitive to natural fillings. They are easy care products. Natural Natural products are light, warm, breathable, resilient and last longer than most synthetic quilts. They are soft to touch and provide plumpness and loft without being heavy. Natural fillings drape naturally and transfer moisture away from the body. close this window