Third Eye — an antenna implanted into skull that let humans to ‘hear colours’

It’s a cybernetic third eye of sorts useful for achromatopsia patients who can see only in greyscale, the world in black and white – literally.
For them, the sky is always gray, flowers are always gray, and television is still in black and white. Using this device they can “Hear” colours after having a camera device attached to a chip in skull that detect colours and converts into sound vibrations.