The Honeywell H49B-1017 Humidistat is top-of-the line, going beyond the usual thermostat control and expanding your home into a humidity-controlled space as well!With sail switch the H49B1017 is excellent for sensing humidity and alerting your system! THE EXTERNAL KNOB ON THE FRONTVIEW ENABLES EASY CONTROL POINT ADJUSTMENT! Order your Honeywell H49B1017 for a completely comfortable house.