[Heatgain]

We have 2 tint laws that I can utilize as a Magistrate in Alabama.
The State tint law, which cites transmission percentages and therefore requires a LEO to have a meter in order to enforce that statute.
But we also have a local (municipal) law, which states if the tint is dark enough to obscure the driver and prevent an officer from seeing and recognizing features of the driver's face, then that's a citation, no meter needed.
You'd better check your state AND local laws.