A method is provided for converting a digital colour image to a digital colour image with improved colour distinction. The housing forms a first latch portion and a second latch portion, the first latch portion and the second latch portion being arranged at a circle. The first signal upon emerging from the first delay line is sent to the second delay line behind the second signal. A strain gauge cooperative with the carrier such that a measured resistance change in the strain gauge corresponds to the soluble plug in contact with the liquid coolant.