Rasagar/Library/PackageCache/com.unity.render-pipelines.high-definition/Documentation~/snippets/shader-properties/surface-options/coat.md

Coat Indicates whether to apply a dielectric coating layer to the base layer. This is a complete covering that has no independent material lerping or mixing. The coat has an independent roughness, a configurable index of refraction, and an extinction/absorption effect with a configurable thickness. The coat layer is not anisotropic.