八達通
The Octopus card was originally introduced for fare payment on the MTR; however, the use of the card quickly expanded to other retail businesses in Hong Kong. The card is now commonly used in most public transport, fast food restaurants, supermarkets, vending machines, convenience stores, photo booths, parking meters, car parks and many other retails business where small payments are frequently made by customers. With over 33 million Octopus cards in circulation as of 2018, the Octopus card is used by 99 per cent of Hongkongers.