Made from 304 stainless steel, these can be autoclaved and reused. Tapers are 2" in length and tapers down 2 gauges smaller than each listed size. This calor style means it is cut out at the receiving end so you can insert the transitioning jewelry into the taper for easy slip free stretching. 18G through 00G, sold by each. The size listed indicates the gauge of the inserting jewelry. The widest outer diameter is larger than the gauge size to allow for jewelry to sit inside. See chart in images.