This battery-powered alarm clock requires three AAA batteries (which ... and indoor temperature, and has an icon that indicates when the alarm is set. One fan raved: “What a deal, I just put ...

【Alarm Clock Battery Operated】This basic alarm clock is powered by 3 xAAA batteries only (not included), which can keep Constantly Big 4.5'' LED digit time display for more than 12 month ...

Basic alarm clock & battery operated clock - This clock is powered by 4 x AA alkaline batteries only (not included), which can keep Constantly Big 1.2'' LED digit time display for more than 12 months.

Remember when alarm clocks were small, battery-powered, and lasted forever ... setting to Automatic by tapping the brightness icon until an A appears, or else you’ll be awake all night).

All have backup-battery capabilities (though a battery may or may not be included) that save the clock’s time and alarm settings in case of a power outage, or if the clock is accidentally unplugged.