RF means Radio Frequency. It refers to tiny labels, tags or plastic modules, that respond when a specific Radio Frequency reaches them.

RF also refers to the devices that are used to read and write information to and from these tiny labels, tags or plastic modules using a Radio Frequency emision.

RF even refers to printers that are used to print labels or tags and at the same time write to an read (i.e. confirm) that the tag has the correct identifying code, or number.