the top or side of each faregate rather than inserted into a slot. Because the card has a radio-frequency identification (RFID) chip inside, it does not need to be touched directly to the target, just held near it; thus the card can be scanned while still inside a wallet or purse passed over the target, affording some speed and convenience over the paper farecards which were physically inserted into a slot. Unlike some systems in which only the card number is stored on the chip and is linked to an account on a network which contains the remaining value, in this system, the remaining value is stored on the card itself, not on a network. Therefore, the card must be present to reload it, and when adding the card to a smart device, the card must remain in close proximity to the device during a process in which the data is deleted from the card and stored on the device. This means that once the card is added to a device, the physical card becomes unusable, and only one device can carry it at a time. In the Metrorail system, using the card to activate the target by will display the value remaining as the faregate opens, both when entering and exiting. On Metrobuses, the farebox will audibly beep and display the remaining value. In all cases, the appropriate fare is deducted automatically, accounting for any applicable transfers and discounts. In an effort to reduce fraud and waste, Metro announced in October 2008 that it would be eliminating paper bus transfers effective January 4, 2009. All riders who wished to take advantage of reduced-fare transfers were required to pay using SmarTrip. Paper bus passes were eliminated in January 2011 and passes are now only available on SmarTrip. For SmarTrip, pass rules are different from CharmCard. All Metrorail passes are now available on SmarTrip. These include One-Day, 7-Day, and 28-Day fast passes valid for unlimited travel on Metrorail. A 7-Day Short Trip Pass is also sold, allowing unlimited off-peak rides, and unlimited peak rides for trips costing up to $3.50, with the difference in fare deducted from the stored value on the card if necessary. CharmCard allows a maximum of two of each pass to be stored, so two day passes and two monthly passes, plus cash, can be stored on the card. Metro also sells SmarTrip cards that are preloaded