Octopus card
The Octopus card is a reusable contactless stored value smart card for making electronic payments in Hong Kong. Started in September 1997 to collect fares for the MTR, the Octopus card system is the second contactless smart card system in the world, after the Korean Upass, and has been widely used  for all public transport in Hong Kong. It led to the development of Oyster card in London.