The HG110-D, a triple-listed thermostatic mixing valve, delivers water at a safe 120 Degrees F (49 Degrees C) or lower from all outlets, while allowing the water heater to be set at a germ-killing 140 Degrees F (60 Degrees C) or higher which aids in preventing the growth of Legionella bacteria in the water heater. The higher tank temperature means that hot water demands can be satisfied longer. Robust, low complexity construction. Every valve is tested for performance prior to shipping. Adjustable and lockable mechanism minimizes unauthorized tampering with valve setting. Each Heatguard valve is factory set and locked to a maximum 120 Degrees F (49 Degrees C). Adj. Outlet temperature range: 85-130 Degrees F (29-54 Degrees C).