The Silentnight Self-Heating Mattress Topper has a unique three-layer construction that adds an extra 7.5 tog of warmth to your bed. Featuring a heat-reflecting foil, thermal lining and a deeply filled quilted top, this mattress topper keeps your bed warm and cosy without the need for electricity, saving you money on your energy bills. The top layer is quilted with super soft fabric and deeply filled for added comfort and warmth. It has elasticated straps to easily fit your mattress and will see you through the chilly winter nights. It is designed to reflect and retain the body heat of the user and is designed for customers who want to avoid increasing fuel bills and concerns about sleeping on or with electrical items. On this topper, the rate of heat production exceeds the rate of heat loss therefore the temperature rises while using, consequently self-heating.