Note: if you want the pistol grip version without microphone, click to this megaphone page.
Designed for professional use in large open spaces up to 1km, the heavy duty models are not as effective indoors (unless you are in an aircraft hangar!). However, these are designed for constant use in all manner of situations.
It has a siren switch and a shoulder strap and takes 8 x C-size batteries (see options below). The build is solid and superior and a 5m car charger lead as an alternative to the batteries.
Suitable for professional use in large open spaces and where more durability is required