Controllers with monitors are a step above the basic controller. This class of controller not only allows adjustment to some aspect of your custom PC water cooling system, but also includes a monitor for that and often other parts as well. Like the more standard controller, these will allow adjustment of fan speed, pump speed, and RGB lighting. In addition they will show you the current status of different areas of your PC. Water temperature, case air temperature, fan speeds and voltage, pump speed and voltage, lighting colors and settings – any of those can be seen with a controller with a monitor.