Great for waking even the sound sleeper in time for school or work or for household safety purposes. Generally a device used as alarm clock and telepohone signaler for deaf and hard of hearing iindividuals; plug into telephone jack using telephone coupling device, plug into AC wall outlet; Sleep peacefully knowing you or your loved one will wake for school or work and can be woken for any phone call, especially for emergencies; place alarm clock near bed, place vibrating paddle under mattress for vibrating alert to time to wake or incoming telephone call; also has extra loud alarm/telephone signaling and strobe light signaling; When woken to sound, vibration and/or light, you know either it is time to wake up or the to answer the telephone for incoming call. Great for low vision individuals because clock has extra large, bright red LCD numbers on face of digital clock and strobe signaler.