What is a sub surface shader?

IceDragonArt

I know what a shader is, I am assuming that sub surface means underneath something but not sure how to do this or what the effect is supposed to be?

Richard Haseltine

Sub-surface scattering (SSS) is a technique for mimicing the way light behaves when it meets certain substances, most notably skin. SSS shaders are used for skin, and also for things like wax.

IceDragonArt

Ah I see thank you!