Dive Alert-Plus v.2 is a specially designed, small, lightweight air horn that uses quick-connect/disconnect hose couplings to become an integrated part of your power inflator, breathable/inflator and buoyancy compensator. Installation is easy and only takes a moment. Dive Alert-Plus does not require any modification of your other equipment, and it does not interfere with the normal operation of your other equipment. Dive Alert-Plus enables divers to signal both above and below the water's surface. There are two different models available; one for approximately 85% of standard power inflator mechanisms model DV1. There are several breathable/inflator mechanisms that require a larger coupling for a higher flow of air so there is the DV3 model to accommodate them. Why have Dive Alert Plus? What would you do in a diving emergency if you needed to get the attention of the pick-up boat or someone else on the water's surface? Before Dive Alert-Plus Scuba divers had relied on whistles or a SMB (surface marker buoy) as their only signaling devices in such an emergency. But if the diver is disabled and can't blow into a whistle (or deploy the SMB) the whistle makes no sound at all. Or if the boat operator is not looking in the direction of a diver with a SMB deployed (if the diver was able to even deploy the SMB) the diver goes un-noticed. Or, what would you do if you wanted the attention of your dive buddy underwater, for whatever reason, and he was simply distracted and not paying attention to you at that very moment? Traditionally, you would be forced to swim up to him or her until you got their attention. In contrast, Dive Alert-Plus enables divers at the mere touch of a button to generate a loud blast of sound on the surface that can be heard up to a mile (1.6 km) away! Or, by switching the Dive Alert-Plus diverter valve for subsurface signaling the diver can now signal for his dive buddy's attention underwater! When you need to get someone's attention on the water's surface, you simply select AIR operation with your diverter valve, press the button and Dive Alert-Plus uses a small amount of air from your Scuba tank to make a piercingly loud sound. Or, when you want to get someone's attention under the water's surface, you simply select H2O operation with your diverter valve, press the button and Dive Alert-Plus uses a small amount of air from your Scuba tank to make a percussion noise to alert your dive buddy. The Dive Alert is manufactured with a durable impact resistant injected molded thermoplastic body and internal elements, stainless-steel horn & buzzer diaphragms and quick-disconnect/connect coupling are chrome plated brass. DV1:Fits All Standard InflatorsDV3: (For BCD's with an Air 2 Octo/Inflator combination).ScubaPro Air 2TUSA Duo-AirAtomic SS1Sherwood GeminiZeagle Octo-Z Dive Alert Plus v.2 Features Signaling Device: Surface & Underwater Signaling Device New Look, Slick Re-Design Audible Surface/Underwater Signal Small, Lightweight Air Horn Uses BCD Quick-Connect/Disconnect Hose Couplings Integrated Part of Power Inflator, Breathable/Inflator Installation: Easy & Only Takes-A-Moment Why Have Dive Alert?Excellent Signal Device for DivingMust-In-Diving EmergenciesBeing Heard, Not Hoping to-Being-SeenLouder than WhistleSafer than SMBHelp: Only-A-Push-of-A-Button-Away Can-Be-Heard 1-Mile (1.6 km) Away! Piercingly 132db Loud Sound 100 psi (6.9 bars) Gives Full-Throated Screech Underwater: Produced by Percussion Buzzing Noise Noise Made by Piston Hitting Stainless-Steel Diaphragm, Like-A-Drum Construction:Body & Internal Elements: Durable Impact Resistant Injected Molded ThermoplasticHorn Diaphragm: Stainless-SteelActuator Valve & Quick-Disconnect/Connect Coupling: Chrome-Plated Brass