SimpleMonitorOff enables the powering down of monitors when the PC is locked.
Normally when locking your machine, the monitors do not power off immediately continuing to consume power. SimpleMonitorOff is designed to detect when you have locked your machine and requests that the screen(s) be powered down. Shortly afterward your screen(s) will power down (i.e., go into standby mode).
After you have locked your machine and the screen(s) have powered down, and you want to unlock the machine, all you need to do is move your mouse or press any key. These actions will wake the monitor(s) allowing you to unlock your machine.
One nice thing about SimpleMonitorOff is that it does not require any additional hotkeys, mouse clicks, or shortcuts â€“ it responds to events sent by Windows directly. This process allows it to respond to you locking your machine regardless of how you choose to do it.