Promate Cardo - Mobile Card Holder Rear Sticker is a smart, sleek and convenient way of carrying all of your metro card, ID's or business cards without carrying them around in your pocket. This slim card pouch attachment allows you to use your phone as an extension of your wallet. Attach it with the patented 3M adhesive and you are all set to put your valuable cards securely in place at the back of your phone. With the rise of smart cards, just put it on the back of your phone, wave it in front of the terminal at restaurants, bus stations, train stations, etc. and your transaction is complete. No need of searching around your pockets or inside your wallets just to pay for your smart card transactions.