La Crosse Technology TX59UN-1-IT Wireless Thermo-Hygro Sensor for Professional WS-2800 Weather Series Transmits temperature and humidity Over 200-feet transmission range Swiss sensor Temp range: -40-degree F to +139.8-degree F (-40-degree C to +59.9-degree C) Humidity range: 1-percent to 99-percent Transmits temperature and humidity Over 200-feet transmission range This works with firmware 332 and 333. Will not work as a replacement with any other firmware. Firmware number can be found by putting batteries in the display; number will flash in the lower left corner. Temp range: -40-degree F to +139.8-degree F (-40-degree C to +59.9-degree C) Humidity range: 1-percent to 99-percent