RFID Tags

http://www.engadget.com/2011/04/20/that-hotel-towel-youre-stealing-might-have-an-rfid-chip-in-it/

http://blog.atlasrfidstore.com/what-is-rfid-used-for-in-applications

http://rfidarena.com/2014/3/4/7-unexpected-and-awesome-uses-of-rfid-tags.aspx