The Stingray is a brand name of an IMSI catcher targeted and sold to law enforcement. A Stingray works by masquerading as a cell phone tower—to which your mobile phone sends signals to every 7 to 15 seconds whether you are on a call or not— and tricks your phone into connecting to it. As a result, the government can figure out who, when and to where you are calling, the precise location of every device within the range, and with some devices, even capture the content of your conversations.
Source:
https://www.eff.org/deeplinks/2012/10/stingrays-biggest-unknown-technological-threat-cell-phone-privacy
