The SV40 is a very compact self-contained tide gauge that can accurately measure changes in temperature and pressure. The product has high precision, small size and buit-in battery power supply. It can be easily installed on various objects such as seabed, trestle bridge, dock, and anchorage. It is widely used in marine research, harbor, dam monitoring and other long-term underwater survey. The tide gauge does not need an external cable when measuring, and can be suspended by a safety cable. When the recorded data needs to be downloaded, it can be easily removed from the measuring point and download the data.