Sinn Watch 1739 Ag B Black Leather Set 1739.021 Black Leather Set. An inherent combination of watchmaking craftsmanship and distinctly traditional aesthetics defines the style of our 1739 Ag B model. The eyes are drawn to the electroplated blue dial exquisitely decorated with a sunburst finish. Reduced to a minimum, the design focuses on the essentials the hour and minute display. The resulting clarity, skilfully combined with the polished, rhodium-plated appliques meticulously attached by hand, conveys a harmonious overall appearance.