Here is an example post.
(NOTE: www.vaporcloud.com as mentioned relative to the PrimusZ is no longer operational. However the website (and I suppose all the free software Microsoft and Google and Go Daddy use to run things like that) is also a tobacco product.)
This device works with both Android (older versions) as well as iOS. There is also support for Mac OSX and Windows. There are links to free GNU software as well used for on this device.
(There are other bluetooth mods around from Chinese companies, Smok I think makes or made one, for example. They mostly worked on Android devices.)
Here is the page taken today from the very same iPhone;s App Store (search "GRX 1.0 Controller):
The app, is of course, free. In addition to being a tobacco product it (the app) also powers anything that uses the GRX 1.0 controller.
But the app alone can't power your vape. It requires the additional iOS software and an iPhone.
Hence they are all TOBACCO PRODUCTS.
I have posted on this in the past.
In case there is any doubt see this recent video (taken at 17:30 from the full video at the bottom of the blog).
(NOTE: Software is explicitly mentioned. Also, all the parts and chips inside are now tobacco products too... Wifi controllers, ARM processors, bluetooth tech, touch screens...)
So in case there was every any doubt this video makes things crystal clear.
To paraphrase (she is talking about zero-nic eliquid but the same rules apply here because, obviously, the PrimusZ contains no nicotine and is not made out of tobacco): "If your product is intended to be use for the human consumption of a tobacco product, to alter the characteristics or performance of the constituents of a tobacco product [e-liquid] then it would be a component or part and WOULD BE REGULATED."
This clearly includes iOS 9.3.5 and all prior version and I suppose all future versions.
So if your little Suzy or Johnny has an iPhone in their hands (or a computer of just about any kind save for an ancient mainframe) they would be holding a tobacco product.
Thus if they were in school with said device they would be VIOLATING THE LAW.
If they had their iPhone on a plane hey would be VIOLATING THE LAW.
Full video here (excerpt above at 17:30 or so):