PK003 is a "your-lips-but-better" shade, as in, a natural, healthy color of lips.  Is almost like a liquid lipstick, but I like this much, much better than liquid lipstick, because it is not sticky or heavy feeling on the lips.  Etude House knocked it out of the park with this formula.  I love this so much, I will have to buy more in the other shades, and even buy PK003 for my mother, which she will love.  Highly recommend for women of all ages.  So easy and comfortable to wear.