Because Stokke are always striving to improve our products, we´re offering a heat sensitive drain plug. The plug works by turning colors, giving parents a visual cue, letting them know that the water temperature is getting warmer and needs to be checked. Please note that the plug is not a thermometer. Always double-check the water temperature with your hand to ensure that it is the right temperature for your baby´s comfort and safety. If you are in any doubt, use a reliable thermometer for accuracy.