These roller buckles are cast from solid brass, and then nickel plated for a silver appearance. They have all the strength and reliability needed for use on dog collars, horse tack, etc. They are excellent quality and far stronger than 'wire formed' buckles.
This is a 1/2" (12mm) nickel plated roller buckle. We also sell them in a brass finish and in several other sizes - see below in related products.