Heavy Duty Electronic Sounders for Marine and Heavy Industrial Applications. Weatherproof Alarm Horns & Sirens / Audible Alarm. Max.120dB. Alarm horns with tightly sealed structure has excellent durability. Suitable for vessels, steel industry, and outdoor plant applications. Aluminum housing provides excellent durability. A variety of sound selection between warning sounds, alarm sounds, melodies and voice messages to fit your sophisticated application needs. Can adjust sound volume with the dial built inside the unit. Terminals located inside the terminal box or product.