These are replacement jaws for the Nylon Bracelet Bending Pliers. You will need a drill and bit approximatley 2.3mm to drill the holes in these parts.
I always like to have a spare set of replacement parts when I buy a new tool. You just never know when you'll need them or if they'll even be available when you do. Getting lots of use out of the bending pliers and am ready if/when I need to replace these.