key

Simple trick to turn your key into a beer opener
An extremely simple need is to open a bottle of water, but sometimes it makes us quite uncomfortable when we can't do it.
The formation and development of locks and keys
Keys and keys have been accompanied by humans through many stages in history and change accordingly.
Use your cellphone to lock the hotel room
Travelers at a hotel in Stockholm could use a cell phone instead of a key or magnetic card to open the door.