Dual Frequency T5577 & UID

• Dual Format: Two Chips & Antennas inside  each card.
• All blocks (including Block 0) can be  re-written multiple times 
• Use ProxMark3 (Magic Chinese Guy  function) or libnfc to change UID. 
• Uses "backdoor" technique to  change/rewrite UID. 
• UID can be changed multiple times. 
• Not suitable for MCT Mi fare Classic Tool.  Suitable for MWT Mi fare Windows Tool.
• Answers to Chinese magic backdoor  commands (GEN 1a): YES 
• Suitable for 4 Bytes UID

Please note:

Weak and poorly constructed antennas can cause the card to permanently lock.  Please make sure antenna is well tested and all surrounding EMI sources are  turned off. If you are using a cellphone NFC chip please make sure that your  cellular, WiFi & Bluetooth functions are all turned off before communicating  with card. The card is tested and pre-programmed with a custom UID. If this card  cannot revert back to the pre-programmed UID it is considered locked and not  returnable. We do not provide technical support for this product.