Keychain

Keychains are small and inexpensive enough to become promotional items for larger national companies that might give them out by the millions.

Keychains with an actual chain or string are usually used by personnel whose job demands frequent use of keys, such as a security guard, prison officer, janitor, or retail store manager.

The chain ensures that the keys remain attached to the individual using them, makes accidental loss less likely, and saves on wear and tear on the pockets of the user.

These can include army knives, bottle openers, nail clippers, pill cases, or pepper spray among many others.

A keyring or "split ring" is a circle cotter that holds keys and other small items sometimes connected to keychains.

Either end of the loop can be pried open to allow a key to be inserted and slid along the spiral until it becomes wholly engaged onto the ring.

Most commonly they are simple discs of smooth metal or plastic, typically with a message or symbol such as that of a logo (as with conference trinkets) or a sign of an important group affiliation.

Many fobs are small flashlights, compasses, calculators, penknives, discount cards, bottle openers, security tokens, and USB flash drives.

As electronic technology continues to become smaller and cheaper, miniature key-fob versions of (previously) larger devices are becoming common, such as digital photo frames, remote control units for garage door openers, barcode scanners and simple video games (e.g. Tamagotchi) or other gadgets such as breathalyzers.

Some retail establishments such as gasoline stations keep their bathrooms locked and customers must ask for the key from the attendant.

Key fobs offering added functionalities connected to online services may require additional subscription payment to access them.

More recent models use challenge–response authentication over radio frequency, so these are harder to copy and do not need line-of-sight to operate.

This kind of key fob may have a keypad on which the user must enter a PIN to retrieve an access code, or it could be a display-only device.

[citation needed] According to Guinness World Records, the largest collection of keychains consists of 62,257 items, achieved by Angel Alvarez Cornejo in Sevilla, Spain, as verified on 25 June 2016.

[7] The previous record holder was Brent Dixon of Georgia, United States with the largest collection of keychains, at 41,418 non-duplicated ones.