RM4 pro and HTS2 Sensor Accessory that integrates the functions of temperature and humidity sensor and power cable. Connect the sensor cable between the RM4 pro and USB adapter just like an ordinary USB cable, at the control panel of RM4 pro in BroadLink app, it will display temperature and humidity of the room where the sensor located. Set the triggers, such as turn on your air conditioner automatically when the temperature rises. Have a question? Find answers in product info, Q&As, reviews