Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically stored information. Passive tags collect energy from a nearby RFID reader's interrogating radio waves. These are the type deployed in retail and are typically placed where the barcode is. The most common application is for inventory counting however in recent years other use cases have appeared designed to improve the customer experience. Because only a small number of large retailers have been able to justify the additional cost per product of the RFID tag, this has impacted any major investment in this technology in other areas.