10 PCS Writable 125kHz RFID Sticker Coin Adhesive Back T5577 Proximity ID Card Token Key Tag Rewritable Dia 25mm (Blank Card No Data)

There are two common standards that I've seen around for doors/garages/offices in the 125kHz frequency: HID and EM4100. The first one has two identifiers facility code (fc) and a card number (cn). The second one is just one number. These cards can be programmed to emulate either of the standards. Programming these cards requires some kind of programming device. I had one old hand-held that can only read EM4100 and is easy to use: push the read button, scan a source card, push the write button and put it next to the writable card. Putting the Etekjoy cards for the writing process successfully duplicates the card and now you have two identical cards. Programming the HID standard (typically the cards that have "HID" embossed on them) requires a reader/writer that understands those, like Proxmark3. If you know the facility code and the card number, the command "lf hid clone -w H10301 --fc 123 --cn 12345" will program these Etekjoy cards and you have a duplicate that will read well in other readers. I really like the small size of the card and the fact that it has a adhesive back. It can be attached to the back of the phone inside a case, for example. The card is not flexible and you have to account for the 1mm width. The cards cannot be read without programming first. Each card being under a dollar is a great value.

I purchased these because I got tired of carrying around my key fob. I was trying to minimize my EDC. I figured I always carry my phone so it would be great if I could dump the fob for something I could stick in my phone case. The maintenance guy at my building claimed they could only do the HID brand fobs. So using some equipment my friend had I copied my fob and wrote it to this coin. It worked perfectly. No more fob! My only gripe is these are a tad thick. They won't work in most phone cases. I did manage to get it to work with one of my 3 cases. The adhesive is strong but not strong enough to just stick to the outside of something like a phone that's always in use.

No problem programing the RFID chips for HID-125 Hz protocol. Read test speeds were much faster than I was expecting. I won’t hesitate to buy more of these.

Make sure to check that all of the stickers are writeable. 7 of the 10 tags were empty pieces of plastic. 3 had the t5577. I don't know if this was intentional or not. The working ones work well.

I used these to make duplicate rfid's for the door at work to put on my phone, much easier than trying to remember where the fob is, I almost always have my phone with me. The adhesive is strong and never had an issue of them falling off.

Got these rfid tags when I needed some stickers instead of keychain pieces, and these worked great. My only issue is that they stand out on my black phone case, but that's on me. They are plasticy on the outside, similar to a dry-erase board, so you can't color them in with a sharpie. The adhesive is great, it's held up quite well since I stuck one on my phone case a few months ago. And it hasn't not worked once. Super convenient when my phone's easier to reach than my wallet when my hands are full.

These RFID stickers did exactly what I needed — I used them to copy my cat’s RFID tag so multiple pets could access the same feeder. The cloning process was easy and they worked perfectly with my setup. I didn’t test the adhesive since I embedded them into a pendant shell and covered them with resin to make them more durable — and they still function just fine through the resin, which was great. The only downside is that one sticker arrived defective and wouldn’t register at all. Still, the rest worked great and solved my problem, and even with the one defective sticker it was still a great value for the cost.

Only one entrance to my building can be opened without a key fob, and I hate carrying it with me since my unit has a smart lock. My solution was to use a Flipper Zero (there's another review that said it doesn't work, but it definitely does) to clone the data from the fob and write it to one of these. I stuck it on the back of my phone with super glue (the adhesive works well but obviously wasn't designed to be used like this) and have been using it close to daily for about nine months and have never had an issue. Only slightly annoying thing (not the sticker's fault) is every time I hold my iPhone up to the reader to scan the sticker, the wallet app opens automatically—if you don't want that to happen, you need to disable express transit/payment in the settings app. Overall would highly recommend!

Doesn’t work