Godeson Godeson 88702 Smart Color Coded Tire Tread Depth Gauge (10 Pack)

What is the acceptable color for minimum 2/32 of tire? And which color(s) are for less than 2/32?

Is this gauge display both in 32nds and mm?

Is it true that it's not (numerically) calibrated correctly out of the box?

does the pin stay in place after pulling it off the tire? the ones I have had always get loose therefor loosing the measurement.