UID Changeable Zero 0 block rewritable with 4byte UID. | This NFC UID Card is not suitable for using the nfc mobile phone, mainly used for access control, parking, hotel door locks, apartment cards, etc. | Compatible with all RFID reader to gain access. | Response frequency: IC 13.56mhz. | Waterproof, ABS material, temperature and drop resistance, matte surface feel, thick buckle, sturdy and durable.

Writable & Rewritable: It can be erased and written 100,000 times. Suitable for making new and back-up tags, please use it with 125kHz RFID card writer/copier. | You cannot add them to RFID locks directly,it can't be read before you program the chip,it's original blank chip.Please write data into them by a 125KHz RFID card writer before use. They are blank tags, no data inside. | Can only be read and written by 125KHz RFID writer/copier,CAN NOT WORK WITH ONITY SYSTEM Proxmark3 RDV4 or other device. | Chip: ATMEL T5577 (compatible with other universal 125kHz tags). NOT NFC CHIP,Can't work with NFC Phone. | Frequency: 125kHz; Sensing Distance: 2.5 to 10 cm (1 to 4 inch); Data Storage Life: 10 Years.