The Normals operator allows you to flip the normals of a mesh or to recompute the normals of a mesh.
Smooth Angle - Lets you control the amount of smoothness influencing the shades of your polygons. The default value is 30 and the maximum is 180.
Selection - Lets you specify which component IDs will be affected by the Flip Faces function. Try entering something like 0-10, and notice how only certain portions of your geometry are being affected.
Embedded below is an interactive scene where you can see two different Normal Types applied to the same Head model. Notice how they appear different even though the topology is the same.