This gas horn has an aerosol that is free of hydro-fluorocarbon gases and the use of aerosols containing these gases has been terminated by EU 517-2014 due to the Global Warming Potential (GWP). Gas horns provide a brilliant form of temporary alarm cover and are therefore often used on construction sites etc. Longer and louder at 120dB. 6 units vs 1,430 units previously. Complies with new EU regulations.