Fangrui Product Details 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 : When Your Humidifiers Performance Declines Or The Control Switch Discolors From Long-term Use, This Sleek, Modern White Humidistat Is Not Only A Practical But Also Enhances Your Homes 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