Sinn Watch 857 S. 857.021 Leather Sinn are renowned for their aviation inspired timepieces that are engineered to meet the exact requirements of a professional pilot. This Sinn 857 S watch continues this tradition with a remarkable automatic movement and innovative pilot’s bezel that allows the wearer to measure and check set time intervals. The striking bezel measures to 43mm in size making it instantly noticeable on the wrist while the minute ratcheting and luminous key mark ensure it remains an invaluable instrument in the cockpit. This Sinn 857 S watch continues to impress with its black coated stainless steel case that has been hardened using Sinn’s famous TEGIMENT technology. This impressive innovation makes the metal extremely scratch resistant while also improving its Magnetic Field Protection up to 80,000 A/m.  Hidden within the case is the SW300-1 self-winding movement which provides central hands for hour, minute and seconds and a handy date window at 4 o clock. Each of these functions are neatly presented on matte black dial decorated with numerals, indices and hands coated in luminous colour for easy legibility in low light. Last but not least, this Sinn 857 S watch is fitted with a screw down case back, sapphire crystal glass and a screw down crown to assist in its water resistance of 200 metres alongside a luxurious black leather strap for one final touch of sophistication.