With an extra sensor, a weather station provides you with even more information. If you would like to know more about the weather than can be measured with your current weather station, choose an extra sensor. There are several sensors for weather stations, each with their own measured values. There are sensors that measure how much rainfall there is, but also sensors that measure the wind force. All sensors are extensions to existing weather stations. They can't be used separately and can only be linked to specific products.