> The StingRay is an IMSI-catcher (International Mobile Subscriber Identity), a controversial cellular phone surveillance device, manufactured by Harris Corporation.[2] Initially developed for the military and intelligence community, ....

> Active mode operations

  1. Extracting stored data such as International Mobile Subscriber Identity ("IMSI") numbers and Electronic Serial Number ("ESN"),[9]
  2. Writing cellular protocol metadata to internal storage
  3. Forcing an increase in signal transmission power,[10]
  4. Forcing an abundance of radio signals to be transmitted
  5. Interception of communications content
  6. Tracking and locating the cellular device user,[4]
  7. Conducting a denial of service attack
  8. Encryption key extraction.[11]
  9. radio jamming for either general denial of service purposes[12] or to aid in active mode protocol rollback attacks

> In active mode, the StingRay will force each compatible cellular device in a given area to disconnect from its service provider cell site (e.g., operated by Verizon, AT&T, etc.) and establish a new connection with the StingRay.[13] In most cases, this is accomplished by having the StingRay broadcast a pilot signal that is either stronger than, or made to appear stronger than, the pilot signals being broadcast by legitimate cell sites operating in the area.[14] A common function of all cellular communications protocols is to have the cellular device connect to the cell site offering the strongest signal. StingRays exploit this function as a means to force temporary connections with cellular devices within a limited area.

So does that mean it would show up as a different carrier on my iPhone, or I'd be blind to the tower choice?

from https://en.wikipedia.org/wiki/Stingray_phone_tracker