The cover is made of 100% cotton fibre, a natural and skin-friendly material. Because this product can regulate the temperature of your sleeping environment, this product contributes to an optimized individual sleeping climate and ensures restful sleep. If necessary, excess heat is stored or released to ensure a balanced sleeping climate. This is achieved by means of thermoregulating microcapsule technology. Depending on the temperature rise or fall, the microcapsules adapt to the situation to create a cooling or warming effect. The fibres of your duvet filling are strictly selected and controlled to ensure a high-quality standard.