This particular Adamas guitar was custom built for Allan Holdsworth (Soft Machine, Gong, Bruford, UK) in 1984 and I was able to recently acquire it on the 2nd hand market.  It is a standard model 1687 Adamas except for one very important difference.  This is a Shallow bowl.  Not only that, but it is a NON-cutaway Shallow bowl.  The few custom Ovation and Adamas guitars with this configuration of bowl are obviously extremely rare.  The 1687 model is normally a deep bowl, but this guitars label says 1687-8S where the "S" stands for Shallow.  The color is the famous -8 Adamas blue.  Arguably one could call this a model 1887.  Standard features include the carved walnut bridge and headstock, walnut fretboard, maple inlays, OP-24 electronics and gold Schaller tuners.   The comfort of the shallow bowl is quite nice and the acoustic sound produced by this configuration is truly amazing.