I love this duo. The "chocolate" side is good for an everyday natural liner. The "shell" side is a shimmery pink color, great for inner corners and waterline. Amazing :)
First off, I have to admit right away that I haven't used the liner half of this pencil at all, but I love the highlighter half so much that I would buy the whole pencil again!
I bought this to try on my waterline, after seeing a suggestion in Allure to use a light beige or champagne colored liner to give that illusion of brighter, wider eyes (instead of white, which can look unnatural, and certainly does on me). Most liners melt off my waterline within a couple of hours, but this stays on me for almost an entire day, no joke. I also like to smudge it around the inner corners of my eyes. It helps wake my eyes up, and I've started using it for my everyday work look.
Also, Shell is an EXACT dupe for the color of my beloved UDPP in Sin. I swatched them side by side on my hand, and Shell might be a *hair* darker, but just looking at them I can't tell them apart. It obviously doesn't have the same staying power as UDPP, but it's nice to have a cheaper alternative.
The only thing that could possibly make this better is if it was available as a full size pencil by itself. Love it!