Jewelry saw blades - for cutting metal. Come in a pack of 12 - bound with a brass wire. Insider tip. Don't take the wire all the way off , just unwind half way, and slip the blade out of the pack. Keeps the rest neat and tidy and together until you need them next. Size relates to the number of teeth per a given length. Use bees wax or Bur Lube to lubricate, make sawing easier and extend the life of the blade.
