Designed for Compatibility: For 400/500/600/700 series evaporative humidifiers and the 800 steam humidifier. This ensures seamless integration and continued performance of your home humidification system. Manual Control for Precision: The 4655 model does not automatically sense external conditions, requiring manual adjustments. By setting the knob, you dictate the maximum relative humidity to prevent indoor condensation, tailoring the environment to your comfort and seasonal needs. Stylish and Functional Replacement: When your humidifier's performance declines or the control switch discolors from long-term use, this sleek, modern white humidistat is not only a practical replacement but also enhances your home's aesthetic. Flexible Installation Options: Install this humidistat on ducts near HVAC systems or on living space walls. For optimal performance, position it at least 6 inches upstream from the humidifier, ensuring it effectively regulates humidity levels throughout your home. Effortless Installation Process: Easily replace your old humidistat with this two-wire system model. Simply remove the old unit, connect the new one without concern for wire polarity, and enjoy enhanced humidity control with minimal setup. The product appearance and printed words depending on the batch, but this does not affect use. Colour:White Material:Plastic Package Contents: 1 * Humidifier control switch 1 set * screws 1 * sponge pad Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.