The ATC Model 655 timer is an electronic control that will retrofit most round case electromechanical timers. The control performs the same timing modes (ON-Delay or Reverse Start Delay) as electromechanical units, and it is capable of timing ranges from 1 millisecond to 199 hours, 59 minutes. On the bottom inside of the control are DIP switches which can be set, in seconds, to establish the timing mode and time range. Our unit will plug into competitive mounted cases without wiring changes in most instances. Remove the electromechanical timer, set ours, plug it into the electromechanical timer case and you’re ready to run. DIP switch setting instructions for electromechanical timers are supplied with 655 installation instructions.