The Sonic Alert Sonic Boom SBH400ss Extra Loud Sweetheart Alarm Clock with Vibrating Bed Shaker is an alarm clock designed for the hearing impaired, as (in addition its added volume) the alarm clock shakes to alert the sleeper. The SBH400ss clock also has a switch that allows user to select 12/24 hour time. Attachable 12-volt vibrating bed shaker included. Hi/low dimmer switch to sleep better at night. Extra loud pulsating audio alarm with a loud 113 decibel adjustable tone & volume control. POWER: 110 volt power supply. User may choose from 60Hz / 110 volts or 50Hz / 220 volts. Will work with an optional 220 volt transformer. Battery backup to maintain the proper time in the event of a power outage. 113 decibel adjustable tone & volume control. DIMENSIONS: 5-1/2 inches Height x 4 3/4 inches Width x 4 1/2 inches Diameter. 6.5 foot Bed Shaker Power Cord. WEIGHT: 2 pounds. WARRANTY: 1 year.