Dynatek introduced the first and still the only portable pulsatile velocity flow standard in the world. Most other devices can only produce an accurate flow rate, or volume per minute. The EchoCal produces a highly reproducible pulsatile sine wave accurate to within 2 1/2% of the set velocities. Far more important than simple flow studies, velocity is a number that determines such characteristics as cavitation, Doppler measurements and velocity versus time characteristics of pumping systems. This instrument can be used to calibrate or check the accuracy of any flow measuring systems that utilize velocity as their fundamental measurement, such as laser Doppler anemometers, medical ultrasound machines or any other measuring device.