It is a metal tool that is used to secure the rubber band around the scrotum. Don't use household office supplies for banding. The bands should be thick enough and tight enough to lead to castration within a few weeks. Store your castration bands in the refrigerator until they are ready for use. This will keep the rubber from breaking down. Always check the rubber ring for elasticity/ breakage before applying it, simply put it on the tool and squeeze the handles to stretch the rubber ring. It should not break/ rip and be free of any cracks. You will need some antiseptic spray in case of infection. Take your goat kid to the veterinarian at the first sign of an infection.

Summary:
Purchase an elastrator from a farm and ranch supply store. Buy castration bands. Ask your local veterinarian to provide pain reliever and tetanus anti-toxin.