T-4 is a four-channel keyfob designed to operate in conjunction with SATEL 433 MHz wireless controllers. Owing to the use of surface acoustic wave (SAW) ceramic resonator, the device is characterized by reliable operation and immunity to interference. Data transmission between the transmitter and the receiver is implemented using the KEELOQ dynamic code-hopping technology. Such encryption provides a high degree of security, preventing the keyfob signal from being copied and used by unauthorized parties.The device comes with an aesthetic and robust enclosure for protection against impact of changes in environmental conditions. The four control buttons are located in special recesses to prevent them from being pressed accidentally. For easy distinction, the buttons are of different color: red, green, blue and yellow.