Made of steel.
Use this along with water- based lubricant .
You use a 1.2mm taper to stretch a piercing to 1.2mm so that you can insert a bar or ring of 1.2mm thickness.
The same goes for 1.6mm. With a taper of 1.6 you stretch a smaller piercing to 1.6 after which you put a piercing jewelry of 1.6mm thickness in it.