A portable device is beneficial because it does not introduce electricity to the water, as it is battery operated. There is also no chance for the water to break down the integrity of the device; in the same way wiring can be affected on boats in the water, since it is not submerged indefinitely. You can also travel with Shock Alert, LLC and test unfamiliar bodies of water in which you plan to swim. Due to the fact boats can pull up at any time and plug in, it is not recommended to swim in Marinas or at a home dock if a boat is plugged in.