They come in a really good range of colours, from super bright and bold to more subtle neutrals, all of which I happen to own:

They are super easy to apply, have great colour payoff, blend nicely and last for ages once they set. As well as being available individually (£10), you could also buy two sets, each containing 5 pencils, but these seem to have been discontinued now.

Definitely well worth investing in if you are after a decent eyeliner, and probably the only eyeliners I will ever fully use up before getting bored or fed up with and moving onto something new.

Now if they would just hurry up and release the 3 new colours over here that they have in America, I'd be content.