Electrofelon's OP link includes an 8" round recessed downlight that is 1.5" thick, 2200 lumens at 3000 degrees K, and it is wet location rated, air tight and rated for direct contact with thermal insulation. There's a 4000 degree K version of the same with an additional 200 lumens.
I find that an interesting accomplishment. . . being air tight / IC rated. The material science keeps leaping . . .
Let's just be aware that anything around clean/green fads are very hot with patent trolls. People hoard patents for something that's just common intuitive use of prior arts, file patents and patent trolls buy them and sit on them until something becomes a fad or in demand and sue/demand license fees.
What you've got is a roughly 8" round light with a roughly 6" aperture. The thick rim is not decorative. It's a large heat sink. It has what is essentially a circular shaped TV/phone back light sandwiched in between the heatsink and back plate and LEDs illuminate it along the edge in three spots and a low profile ballast is clipped onto the back plate. That's it. Traditional design needs space behind the aperture for optical chamber.
But this thing costs $35 while normal ones that require depth is about 1/3 to 1/4 the price. Also, it's not particularly efficient by any means. comparing 90 CRI versions, the SLD4 3000K is only 56 LPW. the substantially cheaper (also 90 CRI) Home Depot T45 is 71 LPW.
The luminaire, and the box has a Rambus patent stickered, not printed, so perhaps Eaton got patent trolled and I suspect the licensing is the single most expensive component of this luminaire.
For this reason, I would avoid specing a design that forces you to buy expensive patented products and use these if and only when you have to work with existing junction boxes. Gymbal (eyeball) requires mechanical space. Other beam management methods like multi-faceted reflector requires optical chamber. You coudl always convert recessed to surface mount, but not the other way around.
On the back, there is a piggyback LED ballast that says "0.52A DC" (I am not sure if that means the DC component only or if they mean 0.52A RMS. Because... as with most LED ballasts, the regulation along and the directly corresponding flicker mitigation is inferior to fluorescent ballasts and this fixture still contains a fair amount of Iripple, thus flicker index. This luminaire exhibits enough flicker to be detected with a mechanical detector where Philips Advance CFL ballast for 2x13W PL-C do not produce detectable flicker). This LED ballast is a galvanically isolated constant current unidirectional(rippled DC) regulated current power source, which is why it can be wet rated/shower rated. The ballast appears to be set in glue like automotive ignition coil to resist humidity.
