Martin's Authentic Series instruments are exact reproductions of historic Martin guitars. Employing a CAT scan machine located at the Smithsonian Institute, Martin engineers examined every detail of several classic Martin guitars from their Museum Collection in order to bring you these authentic recreations. Martin's Vintage Tone System (VTS) was used to replicate the aged appearance and tonality of instruments from specific decades. VTS removes moisture in the wood utilizing the torrefaction system (a thermal process that involves heating the biomass to temperatures between 250 and 300 degrees Celsius) for unmatched stability and tone that can only be found on aged instruments. In true historic Martin fashion, hide glue is used throughout the instrument's construction.