Felting needles for felting.
You can use them with the merino and the sheeps wool. They come in 3 different sizes. The larger the needle, the thicker the needle is, so the larger the hole there will be in your felt piece. The smaller the needle, the smaller the hole will be, which gives a much nicer finish.
For those of you who know about needle felting, here are the equivalent gauges:
Small = 40 gauge
Medium = 36 gauge
Large = 32 gauge