This model combines all the benefits of Eastman's master luthiers' plate tuning techniques with the special German-style multi-layer spirit varnish also found in our model 405 instruments. Additionally, model 906 is finished with a specialty oil varnish. Eastman Master Series workshop models utilize a special method of plate tuning that helps with the fine-tuning of top and back plate graduations to get the best possible sound from each unique piece of wood. Along with their own technical experiments, Eastman's master luthier research into old master instruments and text come together in the creation of some of the finest workshop instruments available today.