Kahlenberg marine airhorns these came off a cargo ship 3 note very rare custom built model T-3 these are very loud and can be heard 3 to 5 miles on open water requires at least 150 to 180 pounds of air pressure I have them mounted on a handtruck for easy movement and a whistle valve hooked up for air pressure tested and works great they have 7 “ diaphragms and they weigh about 130LBS these were made around the late 1960s or early 1970s