The acoustic safe Shkatka is designed to protect speech information circulating in places where the owner of a cell phone is located, in the event of secret remote activation of the phone for the purpose of listening through cellular communication channels. The design of the device allows you to place several cell phones in it at the same time.
Technical specifications: The noise level at the point where the microphone of the cell phone is located is not less than 100 dB Effective spectrum of the noise signal is 250-4000 Hz