Co2 gauge confusion?

Hello I am little confused about the readout on my Co2 gauge in the picture I know the needle is at 0 psi but what number are the lines that go from there to 10psi? https://i.imgur.com/4N32asP.jpg

the red lines or black? If black it appears to be 0(at the pin) and then 2, 4, 6, 8 psi. Can’t say for sure since I can’t see the entire gauge to determine what unit is being used for each color

Right under the micromatic branding on the gauge does it read PSI and under that BAR?