We made it from the most modern and high-tech material - carbon fiber tape. This tape is designed for heated clothes. It looks like an ordinary silk fabric, very thin and soft. Unlike other heaters, carbon tape emits in the infrared range so quickly heats the whole body and spends less energy. In our project it runs up to 5 hours with 45 Celsius degrees. At 50% it works more than 10 hours! Just cut a piece of carbon and glue contacts with a silver glue.
Unpick the seam. Insert the carbon tape into your toy, pillow or pad.