Advantages in my view:
+ Extremely lightweight (the carbon with the screws feels very slightly)
+ Very good workmanship
+ Practically in your pocket (much flatter than a keychain & scratched my smartphone is not)
+ Easy access -> Key simply push out through the shallow hole.
+ Different thicknesses screws for different numbers of keys
In retrospect, I'm glad I do not for the "Keys Mart keyholder" to have (which also stood in the selection) because the decision Carbocage is very light and also covers better by its width the keys.
