Been after a chrono for a while and after much research I'd decided on a Sinn
So, today this arrived & I'm really pleased with it ... even printed out the spec sheet so I can bore family & friends about it's technical abilities :D
The Arktis 203 is technology built for the most extreme conditions. Like many Sinn watches, this is watch combines functionality, practicality and durability with rugged good looks and ice blue features representing the extreme ice environments which is more than fit for. That which proves reliable in extreme situations is certainly a worthy companion for the hardest situations daily life has to offer. This is an attitude that makes the Sinn 203 Arktis not only a reliable partner for extreme divers in the Arctic Sea, but also for all other watch enthusiasts who want to be sure that their fine mechanical masterpieces can also stand up to tougher use now and then. This watch’s actual test constituted extreme temperature changes, from ticking at 1.6 °C three hundred meters below ice flows to cold polar air at –25 °C, or from a warm South Seas coral reef directly to a coolly air-conditioned restaurant. The watch still working without hitch within these challenging environments are assisted by Sinn’s patented dehumidifying technology, the copper sulplate water absorbing capsule – dehumidifies the movement but protected form the outside environment. This is assisted by the water repelling argon filled cavity. In addition the lubrication of all of the movement’s bearings with an extremely temperature resistant special synthetic oil ensuring the watch’s rate in temperatures ranging from –45 °C to +80 °C. The watch’s Valjoux 7750 movement is modified by Sinn’s engineers, to become a reliable and highly functional movement and ensures that the chronograph functions remain exceptionally precise. All of the functions needed for measuring time, periods of time, and diving times are included. The watch remains highly legible underneath the slightly domed sapphire crystal, even at extreme angles. The buttons and crown are screwed-in, shock-resistant and made water-resistant with two o-rings. The dial is a beautiful shimmering, blue steel that retains its special hue for the entire life span of the watch. It is colour fast and full of contrast, as it is specially treated and galvanized in an electrolytic blue bath. A fired, colourless protective coat of paint secures this process. Polished steel case, screw down case back, pushers and crown with flank protection, shock resistant, anti magnetic, argon fill and copper sulphate capsule, Valjoux 7750, 25 jewel, 28,800 vibrations per hour, stop second hand for accurate setting, sweep chronograph hand, highly luminous super luminova hands and dial markings, special synthetic lubricating oils, 300 metres water resistant, day and date, 12 hour chronograph, divers rotating bezel with minute division and luminous triangle, high grade stainless steel, tested in excess of quoted depth specification – and a ruggedly handsome watch – everything one may possibly need. Width is 41 mm excluding crown and 44 mm including crown Lug to lug is 47 mm, Thickness is 16mm.
tried it on and it nearly broke my arm; a massive watch!.. 
