ColourPop Wavelength is a cool duochrome with a sparkle finish that is limited edition and retails for $9.00. In comparison, Natasha Denona Illusion (423DC) is a cool duochrome with a pearl finish that is limited edition and retails for $29.00.
Natasha Denona Illusion (423DC) is 85% similar — it is less shimmery, lighter, cooler.