The Glashütte Original Senator Perpetual Calendar Boutique Edition was released in late 2015 as a boutique-only version of the Senator Perpetual Calendar. It features a stainless steel case and an exclusive blue dial with Roman numerals, made in-house in GO's dial facility in Pforzheim.Reference 100-02-07-12-01 has an alligator strap and a pin buckle.Reference 100-02-07-12-30 has an alligator strap and a folding clasp.Reference 100-02-07-12-50 has an alligator strap and a short folding clasp