They stated the ring is 13mm wide and 4mm thick, and available in US ring sizes 5 thru 15. So I 3D printed some samples (US ring sizes 12 & 14) and I found they were uncomfortable to wear, stopping normal motion of my fingers. Mind you I don't normally like to wear my wedding ring, but that is partly because of the risk of shorting computers/electronics while I work on them.
The specs for the ring say they are using a Nordic nRF51822 - which gives them an ARM Cortex M0 and BT low energy. I believe the BTLE stack uses 80kB of the flash, so without sufficient time to optimise code they'd probably struggle with the 128kB version and need to go for the 256kB one. Add a couple of additional larger notification LEDs, some push buttons, a chip antenna & jellybeans, some shift registers/LED drivers (12 outputs each) and run the 24x11 LED matrix in Charlieplexing mode, and all you need is software. Total electronics BOM isn't too bad - maybe $10-$20 depending on volume.
Oh, yes... you also need a very thin battery, a battery charging circuit (Qi supposedly, but not on the PCb shown), plus the metal ring itself and glass covers, as well as all the mechanical nouse and sepecialist experience to mass produce the parts and assemble them. And fit it all in mutliple ring sizes!
And on top of that, there is a Qi charging stand to design, build, & pay for.
The IC's are wafer scale BGA, so pretty small. Nordic requires me to register to download the data sheet, so I'm going to guess the main chip is 3.5x3.5mm (I think I saw that quoted somewhere). The sample PCB they show would thus be about 55x7mm (which should just fit in the circumference of a size 5 ring), and the LED matrix about 12x5.5mm. So that is using very small chip scale LEDs, not something handled by your average pick and place, and I suspect easily damaged if the tiny flex PCB is mishandled.
I'm not saying any of this is impossible - but the battery is a big problem, and the BT & wireless charging through a stainless housing (or a copper/LED matrix behind the glass) is going to be awfully tricky to get right. If they do manage to eventually ship anything, I don't think it will be anything like the renders.
Kean