A wonderful alternative to owning two different gouges of the same size:  different grinds on each end of the same gouge, or the same grind on both ends reducing time for resharpening. Overall length is 15.25".

The shaft is 5/8" and is called a 1/2" bowl gouge with the British system of measuring, but a 5/8" gouge in the North American system.  Made from M2 high speed steel . 

The Oneway interchangeable long handle is a good choice for this tool, as would be the Robust Collet system.  Both are on this web site under the category of "Handles."