SonTek, advancing environmental science in over 100 countries, manufactures affordable, reliable acoustic Doppler instrumentation for water velocity measurement in oceans, rivers, lakes, canals, harbors, estuaries, and laboratories. Our instruments use sound waves to tell you how fast water is moving, where it is moving, and even if it is not moving at all. Our customers are scientists, engineers, hydrologists, research associates, water resource planners and anyone that needs to collect velocity (speed) data in every kind of body of water imaginable. sontek.com