Rasagar/Library/PackageCache/com.unity.render-pipelines.high-definition/Documentation~/snippets/shader-properties/transparency-inputs/transmittance-absorption-distance.md

Transmittance Absorption Distance

The thickness of the object at which the Transmittance Color affects incident light at full strength.
This property only appears when you select Box or Sphere from the Refraction Model drop-down. For the Thin model, HDRP implicitly sets this value to the equivalent of 5cm.