Circular Barbells & Concave Tapers Kit (18 gauge 10 gauge) Hendersonville North Carolina 8 Best Small Towns In North Carolina's. HIGH QUALITY stretching kit of 316L stainless steel INTERNALLY THREADED CIRCULAR BARBELL pairs and CONCAVE TAPERS that includes all sizes 18 gauge, 16 gauge, 14 gauge, 12 gauge, and 10 gauge. That's 10 barbells, and 5 tapers!!! Concave tapers have a hollow end, so you can stick the barbell directly into the taper. This makes the transfer of the jewelry so much easier and hassle free. 18 gauge barbells are 3 8 inch in inner diameter and are also internally threaded so there is no chance of getting nicked on external threads. 16 gauge 10 gauge barbells are 1 2 inch in inner diameter. Rather than forcing larger gauge jewelry into a piercing, you can insert a taper and follow through with the jewelry for an easy and almost pain free experience. This is all the jewelry you will need to stretch your piercing and you can buy it all in one purchase. The end of the tapers are slightly larger than the actual size so the jewelry fits snugly into the back.