An alarm clock is a pre-set clock that can make a sound at a specified time to wake up a person and prevent snooze. It should be noted that the Google system displays a gray alarm clock; other systems display a red alarm clock. Therefore, the emoticon can be used not only to specifically refer to items such as alarm clocks that make sounds, but also to be widely used to mean alarms, alarms, "sleep", waking up, and time.
