This shader is similar in function to using a Bitmap map with environment mapping set to Screen as an Environment Map. However, Screen mapping simply chooses a pixel from the map based on the coordinates of the currently rendered pixel. This does not work well with reflections.
This shader is intended as an environment shader (apply as an Environment Map), because it looks up based on the ray direction. It maps the proper direction to a point on the chrome ball and retrieves its color.
This shader can be used either as an environment shader or a texture shader, because it looks up based on the direction of the surface normal. It will map the normal vector direction to a point on the gray ball and retrieve its color.
This is a simple shader that applies a gamma and a gain (multiplication) of a color or map. It provides an alternative way of controlling gamma in 3ds Max. Many similar shaders exist in various OEM integrations of mental ray, so you also can use this shader for standalone mental ray and for cross-platform phenomena development.