Sinn Watch 556 A Vintage Cowhide Dark Brown 556.014 Vintage Cowhide Dark Brown.  Sinn watches are renowned for their aviation inspired designs, and this Sinn 556 A watch continues this tradition by bringing to life an aesthetic reminiscent of cockpit navigation clocks and their rapid and clear readability. The satinized stainless steel case embraces the ETA 2824-2 self winding movement with hours, minutes and seconds function and a date display at 4 o clock. The automatic mechanism also boasts 25 bearing jewels, 28,800 semi oscillations per hour and shock and anti magnetic resistance. Housed beneath the scratch resistant sapphire crystal glass with antireflective treatment is a striking matte black dial which features, like most Sinn watches, numerals, indices and hands coated in luminescence for easy legibility even at night. This Sinn 556 A watch is completed by a classic dark brown leather strap with white stitch detail and a stainless steel buckle for effortless wear and comfort.