RFID Rewritable 125KHz/13.56MHz ID/IC T5577/UID Changeable Black Ceramics Smart Finger Ring for Men or Women, with One RFID Reader Copier for Duplicate (125khz Black 21mm)

Took longer to read the instructions than to actually program the ring. Haven't had any trouble getting any of our fob readers to recognize it, no matter what position my finger is in when I pass it in front of the reader. If people are having problems with it, I'd say it's probably a weak reader rather than a problem with the ring.

When the first unit was delivered DOA, I was annoyed but not surprised. It seems inexpensive electronic gizmos have about a 20% chance of arriving non-functional. I sent back and replacement was ordered. Of course, first I eliminated user error. Don't tell anyone, but I actually read the directions! Then I watched a utube video. And of course, I tried reading several different cards to eliminate the possibility that the original card I wanted to clone was defective. When the second one unit also didn't work, it became obvious there is a quality control problem in the manufacture of the device.

It works

Simple to use and program. Works great. Gloss finish wore off and more of a matte black now.

Can not use while it is still on you'd finger. Pointless!

It looks pretty good but the included ring was EM4100 pre-programmed even though it was supposed to be a blank T5577. Could not erase or write to it with the included reader or a Flipper Zero.

This was perfect for what I wanted and I use the ring every day as a replacement for a Mifare access card (default key UID access). It’s way more convenient than fiddling for my wallet and trying to get my access card read on the reader while bulk or other cards may be interfering with the signal.The ring and the reader both worked perfectly with my access card. The reader was also able to copy my card to some blank cards I had trouble copying with the RFID Tool on an Android phone, but now I don’t need to fiddle with all that.The reader couldn’t copy my Mifare card to a Jakcom R4 ring (which is twice as wide and bulky as this ring) because I think the Jakcom UID cannot be rewritten. Probably wouldn’t wear that ring anyway because of the bulk (photo for comparison).

Used this to copy my HID key fob and it worked. The included copier is very basic and seems to have very limited reading range. I had to take the ring off my finger and put it flat against the copier to make it work, which made me worry the key would have very limited range, but in practice they have about the same range as my old key fobs when used on the real door reader, and it's the copier's range which is limited instead of the ring's.The ring itself also isn't the most attractive ring IMO, it's very basic looking glossy black with a slightly lighter tone around the edge and inside. I would have preferred a silver, gunmetal, or carbon fiber color and finish, and also a wider band with flat edges. They do sell a flat-edged ring with the same specs and material that I wish was bundled with the copier. At least this ring feels quite comfortable to wear due to its light weight, rounded design, and smooth finish. Fashion-wise it's mediocre (not terrible) but I love the functionality and the value.