An electronic rechargeable transportation card. it can be used on all public transportation; taxis, buses, subways, and even many parking garages, A T-Money Card is required in order to get a free transfer between buses and/or the subway.
Seoul gyeo-tong credit card Many peope have a Korean credit card with the T-money function built-in.
This is convenient since it requires no balance to be kept on the card and offers direct billing.