Sinn watch 757 leather sinns 757 model builds upon the successful 756 instrument chronograph some new features were added to make the watch even more functional and tough one of its most prominent characteristics is the extreme protection from magnetic fields the watch comes with valjoux 7750 automatic calibre that performs 28 800 vibrations per hour and has 25 bearing jewels the case is extra hard because of sinns tegiment technology the sinn watches 757 watch has a dehumidifying capsule