Straight off the machine with no additional treatment.

Suitable for: Most Materials 

Additional Cost: None 

Most surface finishes either add material to coat, or remove material to smooth. Coming straight from the machine the part retains the accuracy of cnc, however also shows the marks from cutting. In some cases this can be accepted, and in others desirable.
The standard roughness off a machined part is 3.2 μm (0.0032mm)
With further operations roughness can be reduced to 0.4 μm (0.0004mm) This will add cost to the final part.