Why does a carbon dioxide fire extinguisher have a hard horn at the hose?

A carbon dioxide fire extinguisher has a hard horn at the hose to direct the flow of CO2 effectively and prevent the user from getting too close to the fire. The hard horn helps to contain the high-pressure gas, allowing for a more precise application while minimizing the risk of frostbite from the cold CO2. Additionally, the design helps to focus the discharge on the base of the fire, where it can displace oxygen and extinguish the flames more efficiently.