Sinn 556 Series 556.A.RS Swiss Mechanical Watch with Red Second Hand & 20 Bar Water ResistanceSinn 556. A. RS Description The new model born from Sinn's popular series 556. This model features four indices in Arabic numerals, which are an important component of visibility, and adopts a red second hand from the 556. A series. It is equipped with a Swiss made mechanical movement, double sided anti reflective sapphire crystal, and 20 bar water resistance, embodying the ideal elements based on the fundamentals of a mechanical watch designed for