Moreover, foldable fobs are provided having one or more holes or apertures therein for holding key chains, or other devices for attaching the fobs to other items, such as sets of keys, wallets, or other...http://www.google.es/patents/US7156301?utm_source=gb-gplus-sharePatente US7156301 - Foldable non-traditionally-sized RF transaction card system and method B???squeda avanzada de patentes N???mero