A cheap and inexpensive product had some plastic but was much easier to use than a flat ruler
It's inexpensive and easy to use, it's much better than a ruler which is very difficult to read, it gives me a much better quality and accuracy in things, I need certain millimeters.
Pros
Measuring range: 0-6 inches/150mm; ACCURACY: ยฑ0.2mm; Display: extra large 1/2" x 1 1/2" LCD (13 mm x 38 mm); Resolution: 0.1mm