Firstly, apologies from me, I thought I posted this reply but I just found it in my draughts.
Even though the others already answered you, I spent time on it so I may aswell share rather than delete it.
No, so no need to worry.
I will attempt to break this down for you into small and hopefully easy chunks
The NExT has 2 chips, 1x HF 1 X LF.
(to see the individual chips and the specifications, look at the xEM and the xNT.)
xEM t5577 chip is low frequency and you can change 2 things.
The NExT has a T5577 chip which is capable of emulating a number of different chip types.
including, but not limited to. EM, prox, indala, AWID…
To change modes you will need a special tool.
The Blue cloner (can only write 2-3 types of modes) or a Proxmark
The ID number
Blue cloner (can only copy/write) or a Proxmark (can copy/write or choose your own)
In my opinion a truly great chip and it compatibility with sooo many products it is a must have.
For projects, an xEM Access Controller is a great start
xNT NTAG 216 chip is a high frequency, NFC compatible, NDEF capable, fixed UID chip, ISO14443A.
High Frequency (HF)13.56MHz
NFC so you can “talk” to it with your phone
NDEF NFC Data Exchange Format (NDEF) allows you to write things such as these to your chip ( upto a maximum size of ~ 888 bytes.
using an app such as TagWriter by NXP
The fixed UID means it cant be changed, so for access enrolment for example it needs to be enrolled into the system rather than cloned ID, easy if you own the system, a little more challenging if you don’t.
ISO14443A is very common for HF systems so chances of compatibility are good.
Personally, if I was going to add to this combination I would also get a mifare classic “magic” 1k either xM1 or FlexM1
But yeah, have you read through the vivokey website about the Spark 2.