The Right Blank Tag Makes All the Difference
Having a powerful RFID duplicator is only half the battle. If you write your data to the wrong type of blank tag, your building’s elevator or door reader will simply reject it. We offer the industry’s top three most reliable rewritable formats—T5577, UID, and CUID—to ensure your authorized backups work flawlessly on the first try.
Whether you are a property manager issuing replacement keys, or a smart home enthusiast backing up your apartment fob, these premium rewritable tags deliver professional-grade reliability and lightning-fast read/write speeds.
Choose Your Format:
1. T5577 Keyfobs (125kHz Low Frequency)
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The Legacy ID Solution: The T5577 chip is the industry standard for cloning older, unencrypted “ID cards” (such as EM4100, TK4100, and standard 125kHz proximity fobs).
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Durable & Portable: Encased in a rugged, waterproof ABS plastic shell with a stainless steel key ring. Designed to withstand daily wear and tear on your keychain.
2. UID Cards (13.56MHz High Frequency)
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The Standard IC Backup: Designed to clone standard Mi-fare Classic 1K (IC) cards. The critical feature of a UID card is that Sector 0 (Block 0), which holds the unique serial number, can be rewritten infinitely using standard backdoor commands.
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Best For: Standard office doors, older apartment complex readers, and basic hotel keycard systems.
3. CUID Cards (13.56MHz High Frequency – Anti-Shielding)
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The Ultimate Firewall Bypass: Many modern elevators and advanced access readers have “Anti-Cloning Firewalls.” They send a backdoor command to the card; if the card responds (like a standard UID card does), the reader flags it as a clone and blocks access.
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How CUID Wins: CUID (Careful UID) cards are immune to this. They allow Block 0 to be rewritten via standard APDU commands instead of backdoor commands. To the reader, a CUID card looks exactly like a factory-original card, allowing it to seamlessly pass through advanced anti-shielding systems.
Universal Compatibility
These high-quality rewritable blanks are tested and guaranteed to work with leading diagnostic tools and programmers, including the Proxmark3 V5.2, X7 RFID Duplicator, ICOPY X100, 300CD, and most standard NFC/RFID read-write devices.
📊 RFID 耗材对比指南 (RFID Blank Tag Comparison Guide)
(强烈建议将此表格放在详情页的核心位置，老外极度依赖这种技术对比表)
| Feature / Specification | T5577 Keyfob | UID Card | CUID Card (Premium) |
| Operating Frequency | 125 kHz (Low Frequency) | 13.56 MHz (High Frequency) | 13.56 MHz (High Frequency) |
| Target System to Clone | ID Cards (EM4100, TK4100, HID Prox) | IC Cards (Mi-fare Classic 1K) | IC Cards (Mi-fare Classic 1K) |
| Block 0 (UID) Rewritable? | Yes | Yes (Via Backdoor Command) | Yes (Via Normal Command) |
| Anti-Cloning Firewall Bypass? | N/A (Standard LF) | ❌ No (Easily blocked by modern readers) | ✅ Yes (Anti-shielding capabilities) |
| Ideal Use Case | Legacy access gates, old apartment fobs | Standard office doors, non-firewall readers | Modern elevators, advanced security gates |
| Form Factor | ABS Keyfob (Waterproof) | PVC White Card | PVC White Card |
| Rewrite Lifespan | > 100,000 cycles | > 100,000 cycles | > 100,000 cycles |
⚠️ Important Notice: Please ensure you know the frequency of your original card before ordering. A 13.56MHz system cannot be copied onto a 125kHz T5577 fob, and vice versa. These products are sold strictly for authorized access management, personal backups, and educational security research.
James Smith –
I bought the 100-pack of CUID rewritable tags for our apartment complex. Our new elevator system has an anti-cloning firewall that blocks standard UIDs. These CUID cards bypassed it effortlessly. They work perfectly with my Proxmark3. Highly recommend for any property manager dealing with restricted readers.
Benjamin Flores –
These CUID rewritable tags are the real deal. I use them to clone my work badge so I don’t scratch up the original. The anti-cloning firewall doesn’t even notice. These are definitely premium Proxmark3 compatible tags.
Michael Johnson –
The T5577 keyfob pack is exactly what my locksmith business needed. The ABS plastic is very durable and the rings don’t bend easily. I use them daily as 125kHz blank fobs for cloning older EM4100 legacy systems. Great read and write ranges. Will definitely buy more.
Brandon Hill –
Excellent UID blank cards. I bought the 100-pack for an event I was hosting to use as VIP badges. Writing the NFC data to them was a breeze. They are standard CR80 size and fit perfectly into standard lanyard sleeves.
Kenneth Martin –
I highly recommend the T5577 125kHz blank fobs. We use them for our entire apartment complex. The blue ABS plastic is very sturdy. They program incredibly fast and we have zero issues with read distances.
Paul Taylor –
The T5577 keyfob is fantastic for legacy access gates. I programmed a batch of these for our warehouse staff. The waterproof design is great since they are outdoors a lot. These are high-quality smart card duplicator supplies.
Dennis Carter –
These UID blank cards are flawless. I used an app on my phone to write my office badge data to it. The 13.56MHz IC card responded instantly. It is a very easy and cost-effective way to make a spare key.
Steven Thomas –
These CUID rewritable tags are an absolute must-have if you live in a new building. Standard fobs will get you locked out. This anti-shielding RFID tag is the only thing that works on our system. I copied it using my X7 and it was a seamless process.
Patrick Rivera –
The CUID rewritable tag is premium quality. It passes through our strict corporate security readers without triggering the firewall alarm. The block 0 rewritable feature is fully functional. Very satisfied with this purchase.
Jack Mitchell –
I use these T5577 keyfobs for all my 125kHz cloning jobs. They are incredibly reliable and the chips don’t die after a few months like cheaper brands. These are the best smart card duplicator supplies I’ve used.
Richard Garcia –
The 13.56MHz IC card blanks are exactly as described. I used them to back up my Mi-fare Classic 1K keycards. The UID rewritable block allows for perfect 1:1 sector copies. They are standard credit card size and fit perfectly in a wallet.
Jacob Robinson –
These 13.56MHz IC card blanks are perfect. I use them for an electronic lock system I installed at home. Writing to the sectors is fast and secure. They are great property management keycards for small businesses.
Scott Nguyen –
The T5577 125kHz blank fobs are very reliable. I am an access control installer and I leave these with my clients as spares. The EM4100 rewritable chip is very stable. The blue color is nice and vibrant.
Frank Nelson –
If your clone card is getting rejected, buy these CUID rewritable tags. The anti-shielding RFID tag feature is exactly what you need. I wrote my data to it using the X7 duplicator and it opened my locked door instantly.
Samuel Green –
I love the T5577 keyfob design. It is much more robust than the thin plastic ones. I successfully cloned my apartment gate key on the first try. It is a very simple and effective 125kHz blank fob.
Justin Torres –
This CUID rewritable tag saved me $150. My condo board charges a fortune for a spare key. I copied my original to this anti-shielding RFID tag and it works identically. Bypassed the elevator firewall with zero issues.
Ryan Lewis –
I am very satisfied with the T5577 keyfob. The build quality is much better than the generic ones you find elsewhere. They hold the 125kHz programming without any memory corruption. Perfect for my property management needs.
Jeffrey Ramirez –
I was stuck with a blocked clone until I found these CUID rewritable tags. The anti-cloning firewall on my office door is strict, but these bypassed it. These are the best Proxmark3 compatible tags I have found online. Highly recommended.
Larry Scott –
I highly recommend these UID blank cards. They are my standard go-to for RFID access control backup. They work perfectly with all standard 13.56MHz HF duplicators. I have never had a write failure with this brand.
Jason Clark –
The UID blank card is a solid performer. I use them with my NFC phone app to clone basic Mi-fare cards. The block 0 rewritable feature is fully unlocked. They are very thin and easily fit in the back of my phone case.
Stephen Wright –
The T5577 keyfob is exactly what I needed. I cloned my old teardrop fob onto this smaller, sleeker design. It works perfectly on my office building’s legacy LF readers. The price for a 50-pack is unbeatable.
Timothy Sanchez –
These T5577 125kHz blank fobs are excellent. I bought them to back up my community gate key. The duplicator copied the code in one second. Now I have a spare on my car keys and one in my wife’s purse. Very convenient.
Jonathan King –
These CUID rewritable tags are an essential tool for my penetration testing kit. They consistently bypass standard elevator firewalls. The block 0 rewritable function handles the APDU commands perfectly. Very reliable smart card duplicator supplies.
William Jones –
I purchased the T5577 125kHz blank fobs for my HOA. We issue these to residents for the community pool gate. They clone perfectly using my handheld duplicator. The waterproof plastic shell is a great feature for outdoor use.
David Brown –
If you have an elevator that blocks copied cards, you need these CUID rewritable tags. Standard UID cards failed instantly on my building’s reader. I wrote the dump file to this anti-shielding RFID tag and the elevator accepted it immediately. Perfect solution for modern security systems.
Eric Allen –
Great UID blank cards. I used them to make a backup of my hotel room key so my kids could have their own. It is a perfect Mi-fare clone card. The white PVC is very smooth and high quality.
Ronald Harris –
If you are dealing with modern readers, the CUID rewritable tag is your only option. I tried standard cards and they were instantly blocked. This anti-shielding RFID tag solved the problem completely. It looks and acts exactly like my original key.
Robert Williams –
These UID blank cards are fantastic for standard office doors. I used my X7 duplicator to make an RFID access control backup for my employees. The block 0 rewritable feature works flawlessly. No errors during the cloning process. Excellent value for the 50-pack.
Edward White –
I ordered the 100-pack of UID blank cards and they arrived quickly. I use them to program new badges for our school district. The 13.56MHz IC card format is standard and works with our existing door readers. Excellent product.
Nicholas Young –
I bought the T5577 125kHz blank fobs for my custom car ignition system. The read range is excellent, allowing the sensor to pick it up from my pocket. They program very easily and are incredibly durable.
Gary Walker –
The CUID rewritable tag works flawlessly on my high-security apartment reader. I used the X7 duplicator to write the data. The anti-shielding RFID tag technology is very impressive. I will definitely be ordering more of these for my neighbors.
George Thompson –
The T5577 keyfob is my favorite blank for low-frequency systems. I keep a box of 100 in my truck for service calls. They emulate the EM4100 protocol perfectly. The keychain rings attached are actually very strong.
Brian Perez –
These CUID rewritable tags are top tier. I’ve tested them against three different firewall readers and they passed every time. The block 0 rewritable capability via APDU commands is flawless. Essential for any serious RFID access control backup.
Kevin Lee –
Great UID blank cards for the price. I use them for authorized backups of our office keycards. They are 100% compatible with the X7 duplicator blanks. A very cost-effective way to manage our internal security credentials.
Joshua Jackson –
This CUID rewritable tag works like magic. My Proxmark3 wrote the dump file in seconds. The elevator reader didn’t even hesitate. If you need a true anti-shielding RFID tag, do not waste your money on regular UIDs, get these CUIDs instead.
Jerry Roberts –
The CUID rewritable tag is a fantastic product. Our building recently upgraded to an anti-cloning firewall system, but these tags bypass it completely. They are perfect X7 duplicator blanks. Highly recommend for any IT professional.
Andrew Moore –
I bought the 13.56MHz IC card blanks to create spares for my gym access. They wrote perfectly on my desktop reader. The block 0 rewritable feature is exactly what I needed. Very reliable PVC cards that don’t bend easily in your pocket.
Donald Anderson –
I use these UID blank cards for my smart home NFC projects. They act as a perfect Mi-fare clone card. The memory sectors are fully unlocked and ready to use. They are bright white and easy to print labels on.
Raymond Hall –
Great UID blank cards for the office. We use them to issue temporary access to contractors. They are cheap enough to be disposable but reliable enough to work every time. A perfect Mi-fare clone card solution.
Mark Wilson –
These T5577 keyfobs are very well built. I cloned my parking garage pass onto one so I don’t have to reach out the window with my card. The 125kHz frequency penetrates the plastic housing perfectly for a long read range.
Alexander Baker –
These T5577 125kHz blank fobs are fantastic. I run a dog walking business and need to keep copies of my clients’ gate fobs. These allow me to consolidate everything onto one keychain. Very fast write speeds.
Anthony Gonzalez –
I bought the CUID rewritable tags for a specific high-security door at work. The block 0 rewritable function using normal commands is brilliant. It completely bypasses the anti-cloning firewall. This is professional-grade property management keycards material.
Gregory Adams –
The 13.56MHz IC card pack is a great buy. I use them for testing my RFID reader projects on Arduino. The block 0 rewritable capability is very useful for prototyping. Very high quality PVC material.
Matthew Lopez –
The UID blank card pack is a great value. I manage a small hotel and use these to replace lost guest keys. The 13.56MHz IC card formats perfectly every time. I haven’t found a single defective card in the entire batch of 100.
Daniel Hernandez –
As a commercial locksmith, reliable blanks are crucial. These T5577 keyfobs never fail me when doing an RFID access control backup. They write fast and the EM4100 emulation is spot on. Definitely the best 125kHz blank fob on the market.
Christopher Martinez –
These anti-shielding RFID tags are the real deal. I was skeptical that a CUID rewritable tag would fool my apartment’s new smart reader, but it worked on the first try. It behaves exactly like the factory original card. Fast shipping and great packaging.
Charles Rodriguez –
I highly recommend these UID blank cards for basic cloning needs. I bought the 50-pack to make spares for my family. The X7 duplicator blanks accept the data instantly. Just make sure your system doesn’t have an anti-cloning firewall before buying these.
Thomas Davis –
Great quality T5577 keyfobs. I run a tech repair shop and these are my go-to for 125kHz cloning. The chips are very stable and I rarely get a bad write. They hold up great on a keychain and don’t scratch easily.
Joseph Miller –
This CUID rewritable tag is a lifesaver. My office upgraded their card readers and all my old backups stopped working. Using my Proxmark3 compatible tags, I cloned my badge to this CUID and it bypassed the firewall perfectly. I am very impressed with the quality.