RFID 125 kHz key fobs, a mini-review.

Since I also work with various access control systems, I sometimes use a lot of keys with RFID tags. To be honest, I was just tired of paying three times (and sometimes five times) as much for them, so I went looking for them in China.
Read on to see how it went.

I sometimes use these key fobs by the hundreds, and even a 10-cent difference adds up to $10. I used to buy them locally for $0.6–0.8 each, even when ordering several hundred. Once I started shopping in China, I thought, why pay more?
But this review is less about the product itself and more about the seller, who really surprised me.
I placed two orders. The first package arrived in 8 days, the second in 10 (from when tracking started on the postal service's website until delivery).

The order arrived in a plain envelope. Nothing was wrapped around it; the first time, someone had even chewed a corner of the envelope. The second time, the envelope was delivered right to my door (one surprise after another).


Inside, the key fobs were packed in a fairly thick, heat-sealed plastic bag.
The seller offers three colors: blue, red, and yellow (which looks more like the color of baby poop). I bought blue and red ones.
The pack of blue ones and the pack of red ones went straight to a job site after I checked them; I didn't even keep the envelope. Some time later, I placed a second order for myself, to keep as spares. I ordered blue ones.
Both orders arrived with exactly the right number of fobs.


The colors are very vivid. Each key fob has a serial number stamped on it (it looks like laser engraving).


For comparison, here's a card and key fobs bought locally (black and gray), alongside the ones ordered from AliExpress.
They all look the same as the black one, apart from the color.


But there are some differences. The one I bought from a local company that sells access control and video surveillance equipment doesn't have a serial number.


Naturally, I checked them before confirming the order.
I checked both that the keys worked and that they were unique. To do this, I entered all the keys into the device's memory. If even one key had been duplicated, the device would have reported an error.
Everything checked out; every key has a unique number. I tested them with a homemade device.
By the way, the keys have excellent range: during testing, they worked reliably from about 4–5 cm away.


Originally, I wanted to buy 300 of them, which would have been even cheaper, but I was worried customs might not let them through. So I split the order in two.

So, here's the verdict.
Pros.
Very fast delivery both times.
The correct quantity arrived.
All the key fobs work, and each has a unique serial number.
The price is simply excellent, in my opinion.

Cons.
None found.

I hope this mini-review will be useful to people who work with access control systems, and others too.

P.S. I know rewritable keys exist, but it's easier for me to buy a couple of hundred key fobs for a job site (sometimes five or six hundred) and not have to program a separate code into each one.
P.P.S. And this is extreme—not for the faint-hearted or pregnant women.