This safety valve virtually eliminates the danger of scalding by means of an automatic shut-down when temperatures exceeds approx 48°C. The valve causes no flow restriction, but works instantly when the temperature exceeds the limit, shutting down the water delivery to a trickle. Once the water temperature is normalised, the valve will open, permitting showering to continue. Simple to install between the shower outlet and shower head or hose using standard 12mm (1/2') connections.