The SkyEcho is both an ADS-B IN (receive) and ADS-B OUT (transmit) device.  Range is a function of transmit power.  The SkyEcho has a 20 watt transmit power, which will allow you to BE SEEN by other aircraft and ATC for up to 70km (~40 NM) away.  Depending on the output power of other aircraft, you will be able to SEE other aircraft over 270km (~150 NM) away!