What are the different classes used in the Maturity windows plot?

The classes are calculated from the modelled Vitrinite Reflectance [%Ro] using the following subdivision:

0.25 - 0.55 %Ro : Immature

0.55 - 0.70 %Ro : Early oil window

0.70 - 1.00 %Ro : Main oil window

1.00 - 1.30 %Ro : Late oil window

1.30 - 2.00 %Ro : Wet gas window

2.00 - 4.00 %Ro : Dry gas window

> 4.00 %Ro : Overmature