I went with 040 Don't Let Me Brow'n, a neutral brown with ashy undertones. The texture of the pencil is quite waxy, so it works to hold hairs in place, and the waxiness helps the pencil tip to keep its shape, so you don't have to sharpen this after every time you use this but if you do: you are guaranteed a decent, skinny line to mimic fine hairs.
The other end of the pencil has a handy spoolie to brush the colour through your brows to soften it even more if you were a bit heavy handed. Or just to brush brows into shape before you fill them in a bit.
The only thing that I don't like about this is when it comes time to sharpen the thing its not smooth and easy. The wooden-outside-holder-thingy breaks and splinters a bit, so you need to make sure that all the splinters have been brushed off before you put it near your brows. The last thing you need is a wooden stake in the eye.
Other than that I can't fault this little pencil. It does a stellar job of filling in the baldy bits, holds the hairs in place and isn't too warm/red-toned. And for the teeny price I can live with making sure the splinters are off after I sharpen it.