We stock two basic types of needles, and three specialized types (five different types of needles total). Our basic needles are: Regular, and Crown. In Regular, we stock 36, 38, 40, 42, and 43 gauge. In Crown, we stock 36, 38, 40, and 42 gauge (the bigger the number, the smaller the needle). In addition, we have three specialized needles: (1) Forked, which we stock in 40, 42, and 43 gauge, (2) Single-Barb, which we stock in 43 gauge, and (3) Twin-Crown, which we stock in 40 gauge. As long as the needle size stays the same, the "finest" of the rooting is in the following order: 1. Regular 2. Crown 3. Twin Crown 4. Forked & Single Barb Thus, as long as the needle gauge remains the same, the Forked and the Single Barb needles root the finest, and the Regular needles root the thickest . The Regular needles, as well as the Crown needles, are triangular, therefore they have three edges. The Crown needles have one single small barb per edge (three barbs total), with the barb approximately 1/8" from the tip of the needle. The Regular needles have two barbs per edge (six barbs total), and they are at staggered depths from the tip. The forked needles have a very tiny, almost invisible fork in the tip. And the Twin-Crown needles are described here. For hair rooting, the "fine-ness" of the rooting depends on three factors: (1) the size of the rooting hole, (2) the number of hairs pulled into each rooting folicle, and (3) the elasticity of the medium being rooted into. The elasticity effects the degree that the rooting medium closes back in on the rooting hole-- the greater the elasticity, then the greater the rooting medium will "squeeze", or close back in, on the rooting folicle. For example, rooting into vinyl or silicone will appear finer than identical rooting into polymer clay (before the clay is baked), because both silicone and vinyl are more elastic than unbaked polymer clay. So, the best needle also depends upon the rooting medium.