Tire tread depth gauge

This is my version of tire tread depth gauge, to quickly measure the depth of tread on a tire of a car.

The scale goes from 0 to 8 mm, and only this two numbers are shown on scale! Above there is a "instructions", where it sais there is 1 mm gap between two marks on scale.

I created many versions, it is very difficult to have 1 mm scale, at least with my printer.
At the end I colored the 1mm marks with white corrector, to easily read the marks. Later I colored the 4mm mark with red color, this is limit for winter tires.

There is a small bump on outer part, so the inner part doesn't fall out.

I created it in 0.1 resolution, maybe you can try even better resolution.