The Camco Aerosol Signal Horn produces an extremely loud noise that can be used for personal safety, sporting events, camping, boating and other applications. It is audible for at least 1 mile and meets U.S. Coast Guard requirements for boats less than 65.6 feet/20m. The signal horn is refillable with Camco's Aerosol Signal Horn Refill Canister (50168). Size: 3.5 oz.