The CWS900 allows a sensor with a special connector to be used in a wireless sensor network; the special connector is available as an option for a large variety of sensors. (See the Compatibility information on the web page.) The CWS900 contains an internal 900 MHz spread-spectrum radio that transmits data to the CWB100 Wireless Base Station or to another wireless sensor. The frequency of the CWS900's internal radio is commonly used in the US and Canada.