A gouge is used to cut a neat channel in your leather, usually on the flesh side, to enable you to make folds or angles in thick leather.
It can also double up as a stitching groover.
This is an adjustable V shaped gouge, which can cut everything from the finest to the deepest of channels in your leather. It can be sharpened on a strop or file card, so it will last you for years.
*Please be sure to wind the blade back into its guard when your v gouge is not in use, to protect both yourself and the cutting edge of the tool!