---
product_id: 46907889
title: "UID Rewrite Changeable 13.56mhz Smart IC Key Tag Writable Zero 0 Sector 0 Block GEN1 Back up S50 1k Card for ACR122U-A9 Device Copier Clone 10pcs/lot by XCRFID"
brand: "xcrfid"
price: "€ 16.22"
currency: EUR
in_stock: true
reviews_count: 8
category: "Xcrfid"
url: https://www.desertcart.at/products/46907889-uid-rewrite-changeable-13-56mhz-smart-ic-key-tag-writable
store_origin: AT
region: Austria
---

# 1K byte EEPROM memory 13.56MHz NFC frequency UID rewritable 4-byte block UID Rewrite Changeable 13.56mhz Smart IC Key Tag Writable Zero 0 Sector 0 Block GEN1 Back up S50 1k Card for ACR122U-A9 Device Copier Clone 10pcs/lot by XCRFID

**Brand:** xcrfid
**Price:** € 16.22
**Availability:** ✅ In Stock

## Summary

> 🔐 Unlock the power of perfect clones—because your access deserves precision.

## Quick Answers

- **What is this?** UID Rewrite Changeable 13.56mhz Smart IC Key Tag Writable Zero 0 Sector 0 Block GEN1 Back up S50 1k Card for ACR122U-A9 Device Copier Clone 10pcs/lot by XCRFID by xcrfid
- **How much does it cost?** € 16.22 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.at](https://www.desertcart.at/products/46907889-uid-rewrite-changeable-13-56mhz-smart-ic-key-tag-writable)

## Best For

- xcrfid enthusiasts

## Why This Product

- Trusted xcrfid brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Bulk Ready:** 10-pack set designed for professionals managing multiple access points or large teams.
- • **High Durability:** Supports up to 100,000 rewrite cycles—built to keep up with your dynamic security needs.
- • **Clone with Confidence:** Easily rewrite UID to replicate lost or irreplaceable M1 cards—never get locked out again.
- • **Seamless Compatibility:** Works flawlessly with ACR122U-A9 and all ISO14443A door access systems for instant integration.
- • **Robust Memory Architecture:** 16 sectors × 4 blocks of 16 bytes each, giving you granular control over access and data.

## Overview

The UID Rewrite Changeable 13.56MHz Smart IC Key Tag by XCRFID is a professional-grade, writable Mifare Classic 1K card featuring a unique rewritable 4-byte UID block. Compatible with ACR122U-A9 devices and ISO14443A protocols, it offers 1K EEPROM memory organized into 16 sectors for customizable access control. Ideal for cloning lost cards or managing secure entry systems, this 10-pack supports up to 100,000 rewrites, ensuring long-term reliability for security professionals.

## Description

Please make sure you know how to use it before purchase !!! Feature This card works the same as normal M1 cards. Works exactly like the MFS501k, with 16 Sectors and 4 Blocks each Sector, but the Sector 0 Block Zero can be writableIt's advantage This is a perfect solution for a lost irreplaceable M1 Cards ID, you don't need to re-enroll new cards. Just program this new MF 1K's UID to the UID of lost card then you have a new Exactly the same card. User definable access conditions & password for each memory block Organized in 16 sector with 4 blocks of 16 bytes each (one block consists of 16 byte)Specifications Protocol: ISO14443A Capacity: 1k bytes EEPROM memory Rewrite Times: 100,000 timesRead Distance: 0 ~ 10 cm(depends on the R/W device) Material: PVCApplication LoyaltyTicketingIdentificationAccess ControlPackage Include 10pcs X UID Changeable IC Tag

Review: These are Gen 1 NOT Gen 2 writeable cards - These are Gen 1 NOT Gen 2 writeable cards. Mifare Classic Tools (MCT) for Android CANNOT write sector 0 on these. I searched for Mifare Classic Tools (MCT) for windows and found Mifare Windows Tool (MWT) which is inspired by MCT but MWT supports Gen 1 cards a well as what I would call 'advanced key retrieval' functionality. ;) With MWT, an ARC122U and a Windows 10 computer these program first time every time. They work great. I was able to backup and copy both the restroom key used at the RV Park I keep my RV in and my datacenter ID badge to access my datacenter. You pick which is more important in an 'emergency' lol either way these worked like a charm.
Review: YES, these ARE UID changeable ("magic card" - Excellent value. I've included photos to show the size relative to a US twenty-five cent coin (a "quarter"). Using my caliper, they measure 31.7mm across (1.25 inches), 39.8mm (1.56 inches) from top to bottom, and 3.7mm (0.14 inches) thick. - YES, the ones I received ARE "magic card" UID changeable. - They scan as ISO 14443-3 Type A, MiFare Classic 1k (generic (unknown) chip manufacturer) - They read and can be written to without any issues or errors, including changing the UID using a Flipper Zero and NFC Magic. - Sensitivity is very good, and the door lock reader that I am using them with reads them immediately without issue. I suspect that the negative reviewers claiming they are not UID changeable or witeable either received the wrong item, or those reviewers do not understand how to write the UID or may not understand NFC protocols, or they need a different format from MiFare Classic 1k. Buyers should note that if cloning a lock key, you will need to understand how to decrypt keys and how to collect lock nonces, and not understanding those things is NOT the fault of these, or any other writeable MiFare classic compatible NFC cards/fobs. Special thanks to the reviewer who left the review at https://www.desertcart.com/review/R39OBEBNAV9KCF/ref=cm_cr_srp_d_rdp_perm?ie=UTF8&ASIN=B0748DBKW2 . Cracking them open to collect and embed the guts is something that I had not considered, and it is a useful suggestion.

## Features

- UID Changeable Zero 0 block rewritable with 4 byte UID. You can through our UID Card Tools read out the dump file , Then back up . The UID Number will be changed
- Please Noticed: It supports original ACR122U-A9 Read Write and Copy Cards. Please make sure you know how to use it before purchase !!!
- Working frequency is 13.56MHz. Compatible with all kinds of door access control system
- Rewrite Writable Smart IC Tag , 1K byte EEPROM Memory , Copy card. Fully compatible to MFClassic 1K,4 byte UID, organized in 16 sectors of 4 blocks, compliant to ISO/IEC 14443A protocal.
- THIS ITEM IS NOT INTENDED FOR USERS UNDER 12 YEARS OLD !

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0748DBKW2 |
| Best Sellers Rank | #332 in Home Security Systems |
| Brand | XCRFID |
| Connection Type | USB |
| Connectivity Technology | USB |
| Customer Reviews | 4.1 out of 5 stars 86 Reviews |
| Manufacturer | XCRFID |
| Media Type | rfid |
| Minimum System Requirements | Windows 7 |
| Model Name | MF1K Key Tag |
| Resolution | 10000 |
| Scanner Type | RFID scanner |
| Unit Count | 10 Count |

## Product Details

- **Brand:** XCRFID
- **Connectivity Technology:** USB
- **Maximum Media Size:** 3.37 x 2.125 inches
- **Minimum Required Operating System Version:** Windows 7
- **Minimum System Requirements:** Windows 7
- **Model Name:** MF1K Key Tag
- **Number of Items:** 10
- **Resolution:** 10000
- **Scanner Type:** RFID scanner
- **Unit Count:** 10.0 Count

## Images

![UID Rewrite Changeable 13.56mhz Smart IC Key Tag Writable Zero 0 Sector 0 Block GEN1 Back up S50 1k Card for ACR122U-A9 Device Copier Clone 10pcs/lot by XCRFID - Image 1](https://m.media-amazon.com/images/I/71djmNuKmuL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ These are Gen 1 NOT Gen 2 writeable cards
*by A***W on May 10, 2022*

These are Gen 1 NOT Gen 2 writeable cards. Mifare Classic Tools (MCT) for Android CANNOT write sector 0 on these. I searched for Mifare Classic Tools (MCT) for windows and found Mifare Windows Tool (MWT) which is inspired by MCT but MWT supports Gen 1 cards a well as what I would call 'advanced key retrieval' functionality. ;) With MWT, an ARC122U and a Windows 10 computer these program first time every time. They work great. I was able to backup and copy both the restroom key used at the RV Park I keep my RV in and my datacenter ID badge to access my datacenter. You pick which is more important in an 'emergency' lol either way these worked like a charm.

### ⭐⭐⭐⭐⭐ YES, these ARE UID changeable ("magic card"
*by P***E on August 13, 2024*

Excellent value. I've included photos to show the size relative to a US twenty-five cent coin (a "quarter"). Using my caliper, they measure 31.7mm across (1.25 inches), 39.8mm (1.56 inches) from top to bottom, and 3.7mm (0.14 inches) thick. - YES, the ones I received ARE "magic card" UID changeable. - They scan as ISO 14443-3 Type A, MiFare Classic 1k (generic (unknown) chip manufacturer) - They read and can be written to without any issues or errors, including changing the UID using a Flipper Zero and NFC Magic. - Sensitivity is very good, and the door lock reader that I am using them with reads them immediately without issue. I suspect that the negative reviewers claiming they are not UID changeable or witeable either received the wrong item, or those reviewers do not understand how to write the UID or may not understand NFC protocols, or they need a different format from MiFare Classic 1k. Buyers should note that if cloning a lock key, you will need to understand how to decrypt keys and how to collect lock nonces, and not understanding those things is NOT the fault of these, or any other writeable MiFare classic compatible NFC cards/fobs. Special thanks to the reviewer who left the review at https://www.amazon.com/review/R39OBEBNAV9KCF/ref=cm_cr_srp_d_rdp_perm?ie=UTF8&ASIN=B0748DBKW2 . Cracking them open to collect and embed the guts is something that I had not considered, and it is a useful suggestion.

### ⭐ Not UID Programmable
*by J***L on December 6, 2023*

These fobs do not show up as Gen 1a nor can you program the UID on them. I even purchased the ACS122U programmer and this also programmer also failed to write the UID. I was able to sucessfully write other cards with the same sequence. Description is incorrect. They can be used as standard MIFARE 1k cards, just you cannot clone other cards to this one.

## Frequently Bought Together

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*Product available on Desertcart Austria*
*Store origin: AT*
*Last updated: 2026-09-01*