Martinshorn, signal horn on an emergency vehicle, compressed air

Ambulance siren hi-res stock photography and images - Alamy

How to differentiate between the sirens of police vehicles, ambulances, and fire brigades - Quora

Uses lung power to produce a signal Intended to assist in personal protection and safety on land and on water Does not use CO2, Freon, or batteries

Attwood 2460-7 Bellow Signal Horn, Lung-Powered, Meets USCG Rule 33 (Annex III) and EPA Regulations, 8 Inches H x 3 ½ Inches W

Emergency signal hi-res stock photography and images - Alamy

Ozark Trail Boat Accessories Sports and Marine Safety Air Horn 1.4 oz

MARTIN-HORN® 2097 GM » Max B. Martin GmbH & Co. KG

Emergency vehicle hi-res stock photography and images - Alamy

Ambulance siren emergency hi-res stock photography and images - Alamy

Rescue horn hi-res stock photography and images - Alamy