Set of 6 nylon inside ring collets and fixture. To use, attach one of the collets to the fixture with the included cap screw and expansion cone. Your ring is then placed over the collet and the screw tightened, expanding the collet and securing the ring in place. The ring can be easily rotated by loosening the screw slightly. The fixture can be secured in any vise or engraving block for stability while engraving or stone setting.