Sinns 900 range of instrument chronographs is the largest one that the company has designed the case diameter is 44 millimetres the 900 pilot watch 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 mechanism and keeps the dial from fogging the watch is also resilient to magnetic influences other useful functionalities inc