Rockin Beads Brand, 40 Nickel Plated Flat Sided 1 Inch Split Key Ring Connectors Steel Alloy 40 Nickel Plated Flat Sided 1 Inch 25mm outside 21mm inside Split Key Ring Connectors Steel Alloy thickness approz 3mm Rockin Beads (TM) Brand comes with Rockin Beads Size Gauge Card