Single stage paints include all the necessary chemicals in the mix to complete the painting process in one step, eliminating the need for a clear coat on top.
The mix Ratio for single stage paint is 8 Parts paint to 2 parts reducer to 1 part hardener.
It does not require hardener but it will give a faster dry time and more durable finish with the hardener.
If not using hardener then mix ratio is 4:1 with reducer.