Sorry about the damaged packaging, i've been waiting to review this for a while!
As the diagram suggests, you simply just use the revolutionary 'triple-point applicator' to dot above the lashline, and as the dots join they form a straight line. Easy! The idea of a 'pen' style is particularly affective as it allows easier grip and you can get close to the lash line, giving the illusion of a fuller-looking lash line.
It looks so simple I can't believe nobody had thought of it before! However, as you can see my camera is zoomed in quite far, and the three 'prongs' are actually really small and don't distribute a lot of product, so actually achieving the line does take a while. Therefore, I do sometimes fill it in by lining it like a normal liner, but the dots make amazing guidelines and have definitely made the process easier. When using gel or regular liquid liner it's near enough impossible to make the line symmetrical, but with the lack of product distributed it does achieve a thin line that can easily be built on, making achieving a matching line on each eye possible.
For £20, this is perfect for anyone who isn't a liner pro (So that's 99% of us!). I'll admit it is expensive, but this liner does not budge until removed with eye make-up remover - making it perfect as a day liner, and then built on by adding a flick and increasing the thickness for the evening.
You can purchase Clarins' '3-Dot Liner' from your local Clarins counter.