Robertshaw 9204V 24-Volt AC Heating Only Deluxe Mechanical Thermostat, SPST (... Heavy Duty Adjustable Heat Anticipator - More anticipation settings to choose from allows use on a wider range of heating equipment No sub-base required - Simple base and cover design speeds installation. Base can be mounted on wall, freeing both hands for wiring. Mercury-Free - No leveling required. Speeds up installation time J-Box Compatible - Not only will it meet code, but it speeds up installation