Thin

This parameter indicates the transparency of the material from the front and from the back. 

Opacity

Sets the opacity  of the surface.

Roughness

Sets the roughness of the surface for each side. Range  is [0..1] where 1 is very rough,

Specular Level

Higher specular level makes the surface reflective and a lower specular level makes it more diffuse. Range is [0..1].

Occlusion Distance