What is Gvil?
The whole hide on which Torah scrolls are written in the Yemenite tradition, and what sets it apart from klaf.
Gevil is the whole hide of the animal, after the hair is removed, on which Torah scrolls are written in the Yemenite tradition.
How are klaf and gevil obtained? Because the hide is thick, it is cut and split in two: the inner half — the flesh side — is klaf, used for tefillin and mezuzot. The outer half — the hair side — is gevil, on which Torah scrolls are written in the Yemenite tradition.
Unlike klaf, where the hide is split, gvil retains the full thickness of the hide and writing is done on the hair side. Gevil is heavier and thicker, durable for generations, and requires a scribe experienced in its preparation and writing.
This article is written for study and orientation only, based on the cited sources, and is not a halachic ruling. For a practical question, consult a rabbi.