Multi-functional station shows you temperature and humidity indoors and out, as well as up to 3 additional rooms. Displays a smiley face for comfortable room climate, within +66.2F to 77F and 40 to 60%RH range. Displays frowny face, if at uncomfortable levels inside your home. Writable display, pencil only, to identify each room you're monitoring from a storage room, basement, garage or other source. From the garage to the attic, let the wireless technology leave you in comfort knowing room conditions elsewhere. Battery operated, not included, with a 300 foot unobstructed wireless range from wireless transmitting sensors.