LS211 ultrasonic thickness gauge measurements without knowing sound

If only know the thickness of the material but not the velocity of sound,
you can select set by thickness in Linshang ultrasonic thickness gauge，then measure the material with the known thickness,
enter the actual thickness value into the instrument,
and obtain the sound velocity value of the material.
When testing similar materials, you can measure their thickness.
This approach also works for irregular shapes made from the same material.