125kHz RFID
Low-frequency proximity cards
This type of card is widely used in old access control systems around the world. It's pretty dumb, keeps only N-byte ID and has no authentication mechanism, allowing it to be read, cloned and emulated by anyone. A 125 kHz antenna is located on the bottom of Flipper — it can read the EM-4100 and HID Prox cards, save them to memory and emulate any of the saved cards choosing it from the menu.
You can also emulate the card entering its ID manually, so you can easily send it to your friend in text format. Thus, Flipper owners can exchange card dumps with each other remotely.