These MEGAPHONES have a superior audio system with an acoustic range of up to one mile for loud and clear messaging. They also feature a comfortable pistol-grip with trigger switch for onehanded operation. Each comes standard with an adjustable volume control, microphone and alarm siren. Units are powered by eight C-cell alkaline batteries (not included) and measure 14 1/2" L x 9" Dia. Bell weighs 3 1/2 lbs.