paid for with single-ride tokens, multiple-ride Shenzhen Tong cards or 1- day passes. Tokens When using cash, a RFID token (NXP Mifare Classic) is purchased and used for a single, non-returnable journey. There are two different types of tokens, with green tokens for Standard Class, and yellow tokens used for Business Class which is only available on Line 11. All ticket vending machines offer both English and Chinese interface. The purchaser touches a station name to calculate the fare. After payment, a green token is dispensed, which must be scanned at the entrance station and deposited at the exit station. A penalty applies should a token be lost. Purchasers of green tokens cannot ride Business Class on Line 11 directly. Instead, they must get off at any transfer stations with Line 11 and purchase a separate yellow token. Note that as of 2015, many machines accept only 5 or 10 RMB notes. The token(s) are only valid at the station where issued. Passengers are unable to buy an extra token for return journey prior to departure. Baggage X-Ray machines are located at each station, and may be manned during peak hours. Shenzhen Tong cards Shenzhen Tong is a pre-paid currency card similar to Oyster Card system in London and the Octopus card system used in Hong Kong. The multiple fare card stores credit purchased at stations. The card can be used by waving it in front of the card reader located at all entrances and exits to the subway system. Riders who pay for metro fare with a card receive a 5% discount. Since 1 March 2008, riders who pay for a bus fare with a card and then a subway fare within 90 minutes receive an additional 0.4 RMB discount on the subway fare. Card users pay a distance based fare. Since 30 June 2011, cards containing both a Shenzhen Tong and Hong Kong Octopus chip have been available in both Shenzhen and Hong Kong. There are plans to further integrate the two systems, and for a new card which will be accepted all over Guangdong province and China's two SARs. Unlike Hong Kong Octopus Cards, Shenzhen Tong cards cannot be sold back to the stations or have faults dealt with by SZMC. Instead, the customer must go to the offices of Shenzhen Tong. Students studying in Shenzhen can use the Shenzhen Tong to receive a 50% discount. Note