When the microphones are turned on you can’t just shout “Hey, you’re on the air!”. That’s why you need the studio signal light (broadcasters call them “tally lights”). It is available in five sizes with one to five coloured segments. The red segment tells everyone that you are on the air. The other coloured segments can be used to indicate almost anything. A flashing light can replace the ringing of the telephone. Another light can alert presenters to an upcoming break. You will come up with many brilliant ideas.