These Brass open Oval Jump Rings are made in the USA. Outside diameter approx. 16.85x9.25mm, with 17 Gauge (1.15mm thick) round wire. Using Round wire, these jump rings will vary slightly in size and shape and are ready to be plated, or if you prefer, use them as is for an antiqued effect. These have not been tested and therefore, may contain lead. Not recommended for use in children's jewelry.