SIZE-----The Lobster Clasp Is 4cm in Length,1.7cm in Width. Its Ring Inner Diameter is 1cm. The Outer Diameter of The Key Ring is 2.5cm. The Inner Diameter is 2.1cm. The Length of The Special Lobster Clasp is 5cm. The Width is 1.7cm. The Outer Diameter of Its Key Ring is 3cm. MATERIAL-----The Lobster Clasp is Made of High-Quality Zinc Alloy, Well-Made,Durable,Smooth and Shiny. They Have a Electroplate Surface,Which Allows Them to be Used for Long Time with Out Rusting. The Key Ring is Made of Iron. PACKAGE INCLUDES ----- The First Package-20 Pcs Swivel Hooks.The Second Package--50 Pcs Swivel Hooks and 50 Pcs Keychain Rings Come with a Special Swivel Hooks. USAGE-----The Lobster Clasp is Suitable for Keychains,Lanyards,Webbing, Work Cards,Id Document Holders,Bracelets,Necklaces,Wallets,Dog Collars,Mobile Phone Cases,Wristbands,Etc.Sturdy and Durable,Close Tightly,The Buckle is Not Difficult to Open and Have Help Up Well. The Rotating Buckle Has 360-Degree Flexibility and Can be Rotated in Any Direction. AFTER-SALES-----Customer Satisfaction is The Trust In Us. If There is Any Problem with The Product, Please Feel Free to Contact Us.