Smart glasses are ever so slowly returning to public view after the embarrassing flop that was Google Glass. And the latest pair of glasses are meant to get ready for a possible boom: that’s because they aren’t really one pair of glasses, but a hardware platform ready to be customized with any number of sensors and input methods, then marketed for sports use, for industrial applications, or even for daily wear.

The glasses come from a new company called Tooz, which is a joint venture between Zeiss and Deutsche Telekom, the parent company of T-Mobile. Though Deutsche Telekom is involved and ready to shout “5G!” at a moment’s notice (the glasses can support 5G connections, which don’t really exist), the project seems to have been born inside Zeiss and is based on research the company was already doing into smart glasses.

It’s hard to describe Tooz’s smart glasses — named the “Smart Glass Technology Platform” — since they aren’t really one thing. Every time I would ask a question about how they worked, Ersun Kartal, Tooz’s hardware chief, would say something along the lines of, “It depends.”

Basically, Tooz has designed a pair of smart glasses that can support touch controls, gesture controls, button controls, cameras, no cameras, augmented reality, 5G, no cellular connectivity, Wi-Fi, Bluetooth, or any combination of these things, depending on what the partner they’re working with wants to turn them into. If they’re making glasses for runners, they’ll probably have different requirements than a company building smart glasses for an industrial worksite.

There will be one thing relatively consistent between the headsets: the screen. Tooz’s glasses have a display inside the right arm of the frame, which shoots into a mirror and is reflected onto a lens cut into the middle of the right eyepiece. Tooz says that can be customized a little bit, but for the most part, this is how everyone is going to see using the glasses that originate with its design.

I got to try on an early model, and I’m not in love with what Tooz is doing. The technology is still in development (so things could improve) but at present, the glasses’ display appears as a one-inch by one-inch square that’s always in front of your eye — Tooz doesn’t do anything to make it naturally blend into your vision or avoid distracting you. The current display isn’t very good, either, so just imagine having the screen from a bad fitness tracker floating in front of you. (Support for better screens is planned.)

You can turn the screen off so that it’s not in your way, but then you have another problem: the lens that the screen reflects onto is smack in the middle of your right eye, fogging up your vision. Kartal even said it looks “like a fingerprint on your glasses.” During my briefing with Tooz, no one in the room except for me was wearing glasses — which maybe speaks to the product I saw. Anyone who does wear glasses would have pointed out that having any smudge or piece of dust in your vision is distracting. There’s just no way you could walk around all day with that fuzzy lens in your way.

Because Deutsche Telekom is involved, Tooz is also hyping the ability for these glasses to connect over 5G, saying that the upcoming wireless technology will enable the speeds needed for smart glasses to display up-to-the-moment information. I asked why Wi-Fi, Bluetooth, or even LTE wouldn’t work, and the answer I got once again was “it depends.” 5G is supposed to have lower energy requirements than LTE, someone at my briefing said. But Tooz is happy to build glasses that use some other connectivity option — it’s not like they won’t function perfectly well in many use cases. Mostly, I think Tooz is just talking up 5G because Deutsche Telekom was willing to give Zeiss some money to turn this project into a joint partnership.

Tooz says it’s already working with partners to create glasses, and it expects the first pair to go on sale within the next two years. Will those initial models be something exciting for consumers to pick up? Probably not. Even though Tooz has designed some relatively stylish reference glasses, its platform seems like it’s best suited for business and industrial uses — you can imagine Tooz building this tech into a pair of safety goggles, where image quality requirements might be lower. That’s also the only space where smart glasses have really found any amount of success so far; Lenovo sells smart glasses for businesses, and even Google Glass found a second life inside factories.

If smart glasses start to take off, expect more and more companies to look to reference designs like these so that they can quickly get a pair to market — and not always a very good pair. Tooz might be ready to spin up a pair of glasses for whatever application someone can think up today; the problem is, any pair of glasses good enough to get wide adoption likely isn’t something an early reference design will be able to mimic.