Almost every computer, mobile phone, automobile and appliance contains silver. It is the perfect substance for coating electrical contacts – like those in printed circuit boards and switches – because of its high electrical conductivity and durability. Painting silver ink on any non-metal surface provides an electrical pathway, eliminating the need for wires. For example, Radio Frequency Identification Device (RFID) chips with their tiny, thin antennas made of sprayed-on silver, are replacing bar codes on many items in supermarkets and supply chain inventories. Slender silver wires can also be used as filaments-feed for 3D printers to produce intricate items.