Sinn watch 900 pilot s leather the 903 pilot s is a modification of the 903 timepiece sinns largest instrument chronograph 903 pilot s is equipped with valjoux 7750 automatic calibre that performs 28 800 vibrations per hour and has 26 bearing jewels the case is hardened through the use of sinns tegiment technology a dehumidifying capsule protects the dial from fogging another exceptional characteristic is the extreme resistance to magnetic fields the timepiece features various function