Valeport SWIFT CTD probe is an instrument used to measure the speed of sound in the water column. At the same time, it measures the conductivity, temperature and density of the medium that surrounds it, i.e. water. It also has a built-in GPS. It can measure parameters in the water column profile, or continuously while the vessel is moving. The device can be used to a depth of up to 500 m. Communication with a computer is possible via Bluetooth or USB.

The accuracy of sound speed measurement is ~0.25 m/s, salinity ±0.01 PSU, and density ±0.01 kg/m³.