The D-18 Authentic 1939 Aged is built using the same material and techniques Martin was using in the late 1930 such as hide glue construction and hand-scalloped X-bracing. The Adirondack top is enhanced with the Vintage Tone System (VTS), a process that ages the wood to replicate the sound of a vintage Martin. In the Aged version, Martin subtly distresses the finish, giving it the patina of an 80 year old guitar that has been used but not abused. The D-18 Authentic 1939 Aged looks, feels and sounds more like a vintage guitar than any new instrument has a right to.