What lets you perceive color

The wavelength of reflected light, think of the symbol of Pink Floyd when thinking about light and color

Cone cells in the retina of the eye detect color.

There are three types of cone cells.

Two of them detect light of different wave lengths, one medium and the other long.

And the third detects the overall intensity of the light source.

Your brain uses this information to interpret the combination of those three receptors to give you the sensation that you perceive different colors.