Aqua-Data make the best electromagnetic velocity meter in the world, and have been doing so for more than 30 years. Our instruments have no moving parts, can compute flow to ISO748, come with a full tow-tank calibration certificate and will probably never need calibrating again during their lifetime. They are 1% accurate as standard, but can be offered to greater accuracy with additional calibration. We use a state-of-the-art hybrid of analogue and digital signal processing to offer unparalleled repeatability over wide temperature ranges, and they are absolutely unaffected by water turbidity, chemicals or suspended solids.
Fluvia RC3 & FloStick RC4 electromagnetic velocity meters, turbidity meter - more information to follow.