The HS-1 from TrolMaster is used to control commercial dehumidifiers. Most larger / commercial dehumidifiers have a “low-volt” control option so the dehumidifier can be controlled by an external humidistat. The HS-1 works and is wired exactly like an external humidistat. The HS-1 is the best way to control your dehumidifiers by eliminating the need to control the high-amperage / inrush current associated with dehumidifiers.