Used AQUATEC Scuba Alert diving buzzer, underwater air horn, underwater buzzer. Easy to install! An air horn that attaches between the BC hose and the inflator and uses air pressure to produce sound. It's a compact model, so it won't get in the way. *AIR2 only. Please check the appearance in the images. The feeling of scratches and dirt on used items varies from person to person. If you cannot understand the condition from the images, please refrain from bidding and purchase a new item. Please do not offer a price reduction.