Many beginners don’t look at the barometer, either playing too low or too high. Usually we can hit the air pressure to 15psi, which is the red circle 15 pointed by the pencil. Hitting too high is bad for the paddle, too low is not enough stiffness, so 13-15psi is a better choice.
Different barometers have different dials, but they should all hit 13-15psi. But there is a premise that the standard air cylinder quality of the paddle board must pass the test, and the barometer must be accurate. Otherwise, the barometer is inaccurate, and it is difficult to accurately judge the air pressure.