Coat color – Determines the coat layer's color. A texture map can be used here.

Coat amount – Specifies the blending weight of the coat layer. A value of 0 doesn't add a coat layer, while higher values blend the coat gradually.

Coat glossiness – Controls the sharpness of reflection. A value of 1.0 means perfect glass-like reflection; lower values produce blurry or glossy reflections.

Coat IOR – Specifies the Index of Refraction for the coat layer.

Example: Coat Amount

This example shows how the Coat amount value affects the look of the material. The base Reflection Glossiness is 0.76, and the Coat glossiness is set to 0.985. Coat IOR is 2.2, and the Coat color is the default white. 

Example: Coat Glossiness

Coat glossiness controls the sharpness of the coat reflection. In this example, the base Reflection Glossiness is set to 0.76, and the Coat amount is set to 1. Coat IOR is 2.2, and the Coat color is the default white. Notice how higher values produce a glossier reflection and lower values make it look blurry.

Coat bump lock – When enabled, it prioritizes the base bump map during rendering over the coat bump map. You can use it to temporarily hide the coat bump.

Coat Bump Map – Specifies the bump/normal map used as a coat bump.

Coat Bump Amount –  A multiplier for the bump effect.

Coat Bump Type – Allows the user to specify whether a bump map or a normal map effect is added.

Bump Map – Uses a bump map to determine the bump effect of the material.
Normal Map in Tangent Space – Uses a tangent normal map to determine the bump effect on the material.
Normal Map in Object Space – Uses an object space normal map to determine the bump effect on the material.
Normal Map in Screen Space – Uses a screen space normal map to determine the bump effect on the material.
Normal Map in World Space – Uses a world space normal map to determine the bump effect on the material.
From texture bump output – Uses the texture bump output to determine the bump effect on the material.
Explicit – Sets the normals to adhere to a specific value rather than being dependent on a face. As a result, any changes made to the position of a face do not affect the normals, which remain unchanged.