Difference between Flex and X-Series


I was just wondering what the main differences between the Flex transponders and the X-Series transponders are, apart from their form factor.

Also, it looks like the flex transponders won’t be able to be positioned in the webbing of the hand like the x-series due to the amount of movement that happens in that area. Are you guys looking at ways to put the flex transponders in this type of area?

If the flex transponders have greater range than the x-series I will consider switching (if this is possible?)

The flex line will carry a number of different chip types that cannot be or would not be advantageous to be inserted into x-series glass tube. The xNT and flexNT do share the same NTAG216 chip, but with the flexDF, there is no x-series DESFire chip for example.

The primary difference between flex and x-series is form factor, which directly affects tag performance when used with basically every reader antenna design out in the wild. The reason has to do with how the transponder and reader antennas couple magnetically. The cylindrical shape of our x-series transponders does not couple well with the flat spiral plane antennas of almost every reader ever made (some use cylindrical coils but very few).

The webbing area of the hand is suggested for x-series because it is the best, safest place to put an x-series glass tube transponder. The flex is not well suited for this area but it can be placed almost anywhere in the body except gripping surfaces (like the palm of your hand). Putting a flex into the back of your hand, wrist, or even finger is ok.

Check the flexNT product page for a video comparing read range.

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Awesome :slight_smile:
Thanks for information. Having the flex implanted into the finger is a pretty cool idea! Definitely something I will keep in mind once the flex has completed its beta phase.



I was wondering about the differences between the flexNT and the flexDF chips. They both seem very similar and honestly I just want the best one between the two but do not really know enough about these chips to make that proper judgment. In addition are these chips generally better than the x-series?


hi Kory,

“the best one” really depends on what you want to do. “the best” vehicle for winning a race is a race car, not a tractor… but that race car won’t do shit for your fields.

The flexNT is a high performance, longer range version of the xNT. They both use an NTAG216 chip inside, which is ISO14443A and NFC Type 2 compliant.

The flexDF is a high performance ISO14443A and NFC Type 4 implant with the DESFire EV1 8k chip inside. It can operate with multiple “applications” instantiated and has ~8k of total storage.

The flexDF is physically larger than the flexNT but it also has 8 times the storage space. However, the flexDF isn’t necessarily compatible with the same devices the flexNT is. For example, both are ISO14443A and the entire line of Samsung Ezon door locks purports to support ISO14443A tags, however it will not read the flexDF, while it will read the flexNT and xNT just fine.

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Thank you so much,

I would just like to say that I think what you are doing is unbelievable. My whole life I’ve grown up with change and technological advancements all around me. You have taken all of this to a whole new level that I and many others could have never even imagined and I thank you for that.

Also, I would like to ask you one more thing. My question is, is do you have rough estimate to when the Vivokey will be released for purchase? I am hooked on the idea of biohacking and these chips that you are developing. Once again thank you so much for what you do.


Hi Kory,

Thanks for your kind words. The VivoKey has been pushed back so many times. With multiple partners involved, so many things need to fall into place to push things forward, but we are making progress. I feel confident we will be able to launch the beta program this summer.


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Amal and group,

At this point with all the issues with tear on the X-Series, would you recommend just waiting for the beta program to end on the flex and going that route? As someone without any tattoos or piercings and a needle phobia the idea of an 11mm wound is not at all appealing… However the more advanced technology and 8k memory is appealing, as a server engineer the idea of a pki cert or a cipher would be amazing on something embedded.


Hi Cody,

The tear issue only applies to the xEM, not the entire x-series. For example, the xNT supports tear protection on critical memory pages, and the flexNT shares the same NTAG216 chip as the xEM. Also, the flexNT is out of beta now, however the flexDF is still a beta product.



I apologize I must have miss that bit of information great news! Sorry for hijacking this post but on the subject of flashing the module with say an HID image of a badge… Since the xNT has tear protection on the memory pages in the event of a bad coupling, wouldn’t it be safe to use the ‘cheap’ flashing tool? If so why remove it from sale completely and not just warn the end users? Or do your recommend everyone getting into bio hacking to pick up a Proxmark3 and wait for the new cylinder winding?

Thanks for all your help.


Oh I think i found my own answer on that looks like I need the EM for HID, looks like I might have to hold tight for a bit then.