"The device is mounted in a small package and has built-in batteries that are designed for a battery life of 2-3 years. A long battery life is achieved through a special operating algorithm of the device, where most of the time it is in "sleep" mode and consumes very little battery power.
In "sleep" mode, the device does not transmit anything on the radio, making it practically impossible to detect its presence with a GSM signal detector. Additionally, the absence of cables and tiny size would not allow an attacker to find it by analyzing the vehicle's wiring. There is an additional mode to establish the location of base stations for GSM cellular networks, which is useful if the object of observation is in shelters or if satellite signal is silenced by means."