Paper Mart Nickel Plated Key & Book Ring - 1" Diameter- 24 pieces Split key ring connectors are made of durable steel and plated with bright nickel. Inside diameter of 1in. ring measures approximately 7/8in., while the outside diameter measures approximately 1in. Thickness of metal rings measures approximately 3mm or .118 inches. Can be used for a variety of things such as keys, fasteners, craft projects, etc. Sold in a package of 24.