Digital displays, fast response and accurately measures the water temperature in Celsius (?C) only. The Waterproof Digital Shower Thermometer gives a clear indication if the water is warm or too hot or too cold. It has microcomputer technology and semiconductor component that helps eliminate the dangers of scalding and incorporates temperature LED alert. Temperature range: 0 ~ 69?C. Accuracy: ?1?C at 25 ~ 50?C. Respond Time: 2 ~ 4sec. Will fit standard showers with 18.5mm thread at top and 20.5mm at base.