AmpliVox S601 Mity-Meg 15 Watt Megaphone 15 Watt Piezo Dynamic Megaphone 3 Modes: Talk, Siren, Whistle Adjustable Volume Effective range: up to 5/8 mile (900 yards) (822.96 meters) Uses 8 AA cell batteries (not included) for 18 hours continuous use