Replacement Isotemp Thermostatic Mixing Valve to suit all model Isotemp Water Heater.SpecificationsFits Isotemp: All modelsfittings: 1/2″ BSPModel: SFD00011AAWhy a Thermostatic Mixing Valve is essentialAll Isotemp water heater should be fitted with their innovative Isotemp Temperature Control Safety Mixing Valve, this protects users from scalding hot water. Water heated with engine heat exchanges can be heated to 90 C or more which can scald those unfamiliar with boat water heaters. Water will also be heated to 70 C + with just the electric heating element alone. By adjusting the valve, the Isotemp thermostatic-controlled mixing valve mixes the boats water with the hot water to deliver the temperature you want at the faucet. This mixing action also speeds recovery time and extends the volume of hot water you get from a smaller tank.