13.56mhz,ISO14443A Card type: MF-IC (Read only. Not re-writable. ） Suitable for 13.56MHz RFID proximity access control system and ID management system. For example, register them to your RFID door lock as new keys if applicable. Compatible with M1 Card. If your lock uses M1 card, these key fobs work for your lock too. Note: These are 13.56MHz key fobs (tags). If you want to register them to your lock system, please ensure that your system uses the same frequency 13.56MHz.