Alarm Clock -

From the aggressive, metallic ringing of classic wind-up bells to fading music, radio, or gradual volume increases (gentle wake-up).

A nearly universal feature that allows for brief, repeated intervals of extra sleep, often creating a "love-hate" relationship with the user. alarm clock

For those who find traditional alarms jarring, alternatives exist: Simple Alarm Clock - Apps on Google Play From the aggressive, metallic ringing of classic wind-up