A mobile radio frequency identification (RFID) device for use with supply chain operations, association of things, and work in process operations. The mobile RFID device comprises a cart comprising four wheels and a handle for guiding its motion. The cart also comprises a top surface, an open lower shelf below the top surface, and a lower enclosure below the open lower shelf. The top surface of the cart comprises a very refined RF field which only scans items within a defined area. The defined area can be a flat work surface or a recessed well. The top surface also comprises a directional antenna that is completely hidden and communicatively coupled to an RFID reader. The lower enclosure below the open lower shelf is an enclosed storage cabinet that can house an RFID reader, an inverter (DC to AC), a battery, and a charger for the battery.