The MP50 from Pulse is a 25W handheld megaphone with wrist strap and emergency siren.

Specifications:

Power rating (RMS): 25W
Projection range: Up to 500m depending on conditions
Siren on/off switch
Volume control
Microphone on/off trigger switch
Power supply: 8x1.5V D size batteries (not included) or 12VDC (adaptor not included)
Dimensions (ØxL): 230x370mm
Weight: 1.23kg (excl.batteries)