Silver filled wire has a layer of silver that equals 1/10 of the weight of the wire bonded to the outside of the base metal core wire. Silver Filled wire is similar in use as Sterling Silver Wire. It can be polished, soldered and has the same look at a much lower price than Sterling. This wire is 1/10 Silver Filled CDA220, Half Hard, which means that it is 10% sterling silver. With a half hard temper, this wire is suitable for most wire wrapping applications. Made in the USA.