Description: Each has a number mark and place name, which will help you identify the pigeon. Simple design makes it easy to buckle up and remove from your Adopting material, which is non- and without deformation for long term use. SIZE:Inner Diameter(min):Approx. 8mm/0.4inch.Outer Diameter:Approx. 11mm/0.43 Inch.Height:Approx. 11mm/0.43 Inch Red is is US, Yellow White is France, Orange is Taiwai. Specification: Inner Diameter: Approx.0.8cm/0.31 inch Height: Approx.1.1cm/0.43 inch Material: Aluminum and Package Includes: 100 Pieces Pigeon Leg Rings