This is a really-pretty light suited to 4" can light retrofits and to direct mounting on any ceiling junction box.
With circuits on board the light engine, the light is directly powered by line 120 vac. This will mount with ease on a small 3 1/2" ceiling box, mounting screw pitch 2.75", even if the box is well-populated with wires.
Beware though if you have a usual 4" junction box with inch-wider screw pitch. Beware too with any can or junction box open to space inhabited by bugs. The five openings of the back side glow brightly and WILL attract bugs madly seeking celestial navigation. Where an LED light can be maintenance-free forever, it will be quite a shame if one must climb up to twist off and clean the lens.
The bug problem will be huge and certain where these lights are used to improve upon architectural lighting with burned-out halogen bulbs. My adventure with the photo at left is detailed here . My solution for such lighting has been 4" Glimpse, once and still, hard to find. How many of us know that these nice 450 lumens, 3000°K lights are at last fully available at importer Lighting Science ?
The GetInLight 4" will be challenged in serving architectural applications where there is ample energy to be saved, and need to be free of maintenance. Bug paths of the 4" Glimpse can readily be taped-over under-the-lens.
Here the face cavities for screw mounting are readily taped over. The three irregular lens-attachment keyways can not be taped over.
Here is a photo of the light almost-fully installed, not yet with the lens applied. This is in the overhead of a closet, working awkwardly in darkness. Notes on the photo detail missing items in the package, where I was willing to cope, spending a full day in pursuit of needed hardware. By my investment in making things work, then, I hope to work with Amazon to not frustrate the usual buyer
Where I install lights on RACO 175 steel boxes air tight and bug proof, and want lights of about 500 lumens as replacement of 100 watt incandescent in closets, hallways and bath/ shower overhead, I I will have much interest in the 4" GetInLight, perhaps identified by its UPC, X000ZCIY39.
Here summarize some of the package numbers:
550 lumens for 9 watts is efficacy 61 lumens per watt.
Diodes are 3 mm dia., qty 33. There are 25 in an outer circle, and 8 at an inner circle, 57 mm array dia.
Diode area is 233 mm2. Diode luminance is 2.36 lumens per mm2.
Array area is 2552 mm2. Array luminance is 0.216 lumens per mm2.
I believe diode and array luminance are important competitive measures of a light, and that those glare characteristics of 4" GetInLight, are excellent.
At 4/1/2017, add observation that GetInLight 4" lights must be installed with their provided quite-thick foam gaskets. Installation without gaskets was tried with thought there might be a visibly tighter fit against the ceiling. Without the gasket, the lens keys interfere with the mounting plate. Without spacing created by the gasket, the lens does not fully engage, and it is very likely you will have difficulty rotating the lens to detach the light.
See one of the three pinched lens keys just inboard of the four slots at 3.5" pitch of junction box screws.
See a dark luminaire-to-ceiling interface, not reduced by absence of the gasket.
The gasket may be pulled over the dangling luminaire.
Better, pull the gasket onto the luminaire without release of mounting screws.