Please make sure to soak cleaning by fresh water after using the device in seawater, to aviod seawater or any residual foreign objects corrosion on the propeller or other parts. Please make sure the battery charging port do not have any contact with seawater, to aviod seawater corrosion. Please be aware that, for maximum using time, this device can reach up to 70mins, but it may vary due to environment / user's weight or flow resistance.