Orion 8oz Boat Air HornThis marine signaling air horn meets United States Coast Guard requirements for boats up to 65' in length. This 8oz air horn is able to provide up to 106 blasts per can with a 120db blast at 10'. This easy to use horn is a perfect marine signaling device.8oz refill cans available hereAir Horn Operation: Do not shake before or during use; Screw the horn onto the cartridge; It will snap into place (around 3 turns); Hold in the upright position]; Depress the button in a series of short blasts; NOTE: Long continuous blasts will cause the valve to freeze. If this occurs allow the horn to return to room temperature before further operation.Click here for Orion 509 8oz Safety Signal Horn Safety Data Sheet