Heres a simple, low-cost way to keep yourself warmer without an electric blanket. This bed underlay uses reflective aluminium to stop heat escaping through your mattress, creating a warm zone beneath your body. Foam underlay lined with aluminium. - mysmartbuy Heat-Reflective Bed Underlay - Energy Efficient Insulating Foam Mattress Topper Lined with Aluminium in Silver - Size: Single