The coloured operational principle of the TAWATEC E.O.Diver Tactical ICS originates from the use in instruments from air and sea-navigation : The zero point of the titanium bezel is provided with a green H3 tritium tube. This H3 tube stands in relationship with the minutehand. This is illustrated in the lower picture, you see that the bezel is adjusted at a 3 o clock position. Therefore the TAWATEC E.O.Diver Tactical ICS has a green H3 unit on the minutehand. The indices on 12 o clock is equiped with a orange H3 tritiumtube, which has a reference relationship with the hourhand. (a different colour in the 12 o clock position to the other indices is particularly importantly for the arm attitude and the basis for error free reading in the dark) for good intuitive reading we choose a orange H3 tritium tube on the hour pointer of the TAWATEC E.O.Diver Tactical ICS.