Gold filled. c. 1900. XL (5/8" diameter) period-appropriate bolt clip was likely added later, but it's great. 19.25" total length. Probably American. Likely sold through a catalog like Montgomery Ward or Sears on a page with lots of other shapes/textures so you felt like you were getting a "semi-custom" experience by choosing your favorite. Great early sales technique. 3/8" wide links.