It is used as a mifare card, it has backdoor to change the uid of the card.
Price: $25 US Dollar
Description

Change the uid with proxmark3

use hf mf csetuid xxxxxxxx to set the uid.

all the commands that for UID changeable mifare card:

1. connect the pn532 board to pc with a ft232rl usb-uart.
2. download libnfc and compile it. here is howto:
http://www.xfpga.com/html_news/compile-libnfc-for-pn532-breakout-board-14.html



now read the uid of the card, and then change the uid
The uid is 01020304, and we set it to 33333333.


read back the uid to see if it is changed
ok.
Package List
uid changable mifare card with backdoor (1k card, s50 card) x 1
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We will dispatch the items when received the payment.
Shipping time and cost(for reference only):
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Buyer can return the item in the original package within 7 days upon receiving if you are not happy with it. We will refund you or send replacement to you within 3 working day after the item is received.