This is a climate card sold in Korea. It's a set of 3 cards. Unused. You can travel on public transportation (buses and subways) within Seoul for a fixed price. They often sell out at the airport and convenience stores in tourist areas, so it's convenient to get them in Japan beforehand. (You can use it from Gimpo Airport to Seoul, but not from Incheon International Airport to Seoul because Incheon International Airport is outside of Seoul.) You charge the fixed amount at subway stations in Seoul and use it. As a bonus, I will include a Korean entry card. Recently, entry cards are rarely distributed on the plane by low-cost carriers, so it's convenient to fill it out on the plane beforehand, as you can line up at immigration (where you show your passport) earlier. ☆Please refrain from price negotiations.