Light because it is small

Almost all lightweight-eyewear marketing is about material: titanium, beta titanium, memory alloy, carbon fibre. What actually decides the weight is size.

Why not titanium

There is a microphone hidden in the front frame and electronics in both temples. Running a wiring harness through a metal frame is a harder problem — routing space, shielding, assembly yield, every one of them gets more complicated. And we could not find what it would buy us.

TR90 is the nylon used in high-end outdoor sports eyewear. It is very light and very tough, and under load it springs back instead of deforming. It is not the cheap plastic the word "nylon" makes people think of.

It is also workable for us: the microphone port, the wiring channel through the nose bridge and the battery cavity in the temple can all be moulded directly. To get crisp detail we cut a steel tool rather than an aluminium one, and the front frame and the temples are tooled separately, so a future frame can reuse the same temple mould.

Where the weight actually is

Traditional outdoor eyewear is a wrap: thick, wide, heavy. And once the frame is large, the lens has to be large — which is where the weight really accumulates. Lens weight grows with area, much faster than the frame does.

We use ordinary indoor eyewear proportions. Smaller frame, smaller lens, weight saved at the source. The result sits in the same class as the titanium frames sold on being the lightest, and we did not even change material.

It is light because it is small, not because it is titanium.

Why a camera can still leave it lighter

A camera adds weight, obviously. What decides the outcome is not how many grams the module weighs, it is what you intend it to do.

Shooting 4K continuously means the chip runs flat out for long stretches: the power draw climbs, the battery has to grow, the heat has to be dealt with — and the battery is one of the heaviest single parts in a product like this, with the thermal structure and its metal on top of that. Stacked together, those three weigh far more than the camera module itself.

We take photographs, plus five-second clips and interval shots. Between two frames the chip drops back into deep sleep, an order of magnitude down on power, so the battery does not have to grow and nothing has to make room for cooling. The weight that saves is far more than the camera adds.

The result is under 40 grams, carrying a camera, two microphones, two speakers and local storage. Among AI glasses of this class it is one of the lightest — we do not say the lightest, a word people keep taking off each other by fitting a smaller battery and cutting more features.

Past a point, the comparison stops mattering

Five grams is a 15% difference on a spec sheet and not on a face. Once a pair is already light, what decides whether you can wear it for four hours is the contact area of the nose pads, the grip of the temples and where the centre of mass sits — not the last five grams.

So we did not spend the budget pushing the weight down further. That money went into the microphone position and its port structure, where you can hear the difference.