In Roman times, togas had no pockets, so property owners or individual responsible for a storehouse would wear ring with a small key attached to it.
The keyring has evolved a lot since then. From torches to USB’s to bottle openers, everything about it makes our lives easier.
A Keychain is small and inexpensive enough to become a promotional item for larger National companies that might give them out by thousands or even millions for example for the lunch of a new product. We are even able to custom make a keyring for you.