Traffic Lights are common to all. Green is universal to say go, Amber (yellow) get ready and Red to stop, our Indicator2 is this simple. ClockWatch starts an internal stopwatch or uses it to time colour changes in an incremental time.
We use a simple lamp that can change from Green to Amber to Red and/or the LightTower with 360 Degree viewing.
Both of these are connected with standard XLR cable. (user supplied)