AcuRite 13021 Atomic Projection Alarm Clock with USB Charging Projects time on your ceiling or wall, kindly refer the user manual given below for troubleshooting steps. Atomic Clock features split-second accuracy and automatically adjusts for DST Programmable alarm with snooze for daily, weekday, or weekend use USB power port charges your cell phone while you sleep (1.0 Amp output) AC adapter-powered with battery backup in case of power loss