An NFC tag is a small, passive data store that can be read, and under some circumstances written to, by an NFC device. NFC tags work like any other RFID tag, allowing compatible hardware to both supply power to and communicate with an otherwise unpowered and passive electronic tag using radio waves. NFC tags are used for identification, authentication, and tracking, and they typically contain data and are read-only in normal use, but may be rewritable. They can be custom-encoded by their manufacturers or use industry specifications. NFC tags come in various form factors, ranging from small stickers to credit card-like plastic cards. Most NFC tags comply with the ISO 14443 standard for wireless, proximity-based data transmission, and there are five subtypes of NFC, labeled type 1 to 5. Type 1 tags are the least advanced and can store less than one kilobyte of data, whereas Type 5 is more advanced and can store up to 32KB. NFC tags can be used in a variety of creative ways, such as automating tasks and for better communication between devices.