Radio Frequency Identification Devices (RFIDs) is a technology that uses an antenna, transceiver and transponder in conjunction with the radio frequency part of the electromagnetic spectrum to identify objects, animals or people. RFIDs are similar to barcodes except that scanning can take place remotely or covertly. The primary use for RFIDs is logistics — finding things and tracking things — but they can also be used to trigger actions — anything from unlocking a door to carrying out a transaction.