Key Size Required: Accommodates up to 8 standard size flat keys. The inside diameter of the column is 4mm, please make sure your keyhole inside diameter is larger than 4mm.< /p> Allows you to store your existing keys (no need to go to the hardware store to make new keys) and attach your larger car keys with the ring provided. Say goodbye to bulky key rings, holes in your clothes, full pockets and jingling keys - organize that mess and free up your pockets with an organizer! The key ring, ultra light and compact , is made of an aluminum frame and stainless steel parts - the patented S-shaped design makes it an ideal keychain to carry your keys. How many birthday gifts, Christmas or holiday can you do now , is the perfect gift for any occasion, sure to please any key holder.