A daily bath is essential to baby's hygiene and relaxation. The Nuby Bath Time Clock and Thermometer can help keep bath time safe and fun. When placed in bath water, the top part of the display will indicate the water temperature in either Celsius or Fahrenheit. When he light flashes green, the water is too cold, but when the light flashes red, the water is too hot. When the sensor comes into contact with the water, the timer will automatically begin counting up, advising you as to how long baby has been in the bath. Never bathe an infant for longer than 5 minutes.