The MagKey is a device that uses the wonders of magnets to stop your keys from jangling. It's pretty annoying when your keys jangle in and around your pockets, and MagKey helps to stop that annoyance.
Each MagKey pack includes a keyring and a set of 1 mm-thick magnets, as well as an optional keychain. All you have to do is attach the sticky side of a positively polarized magnet to one side of the bow of a key and a negative magnet on the other side. The keys are then threaded onto the keyring, causing positive to attract negative and making the keys stick together, eliminating jangling.
This contraption uses very simple workings but helps offer a lot of convenience.