Sherlo 2 button remote transmitter with black housing is commonly used on alarm systems. The remote uses a super secure code called rolling code, meaning the code sent is never the same. Sherlotronic 2 button remote is perfect for use on gates, garages and alarms. The Sherlotronic remote has a unique clip antenna design increases operating range by 50% the remote also boast approximately 20000 operations on a new battery. The Sherlotronic remotes are also smart, the LED (light) flashes to let you know when the battery is low. Sherlotronic 1 button has multi colored buttons and a steel key ring attachment so it should never break.