The Output utility texture can be used to perform various adjustments to a texture's value, such as multiplication, offset, inversion, and clamping.

UI Path: ||V-Ray Node Editor|| > Shader > Add > Texture Utilities > V-Ray Output

Texmap – Input socket for the texture that will be modified.

Output Mult – 

Alpha From Intensity – Specifies where to take the alpha from.

Bitmap alpha – This is the default setting. With this option selected, V-Ray renders the material the same on both sides. 
Color intensity/luminance – Renders the back side of polygons as invisible for the camera. 
Force opaque – Renders the back side of polygons as invisible to all rays except shadow rays.

Invert – When enabled, inverts the resulting texture color.

Invert Alpha – Inverts the alpha channel if Invert is also enabled.

Bump Amount –

Output Clamp – When enabled, it clamps the output in the [ 0.0; 0.1] range.

Mono Output –