This is for "LOGISYS Computer ML12WT LED Super Bright Sunlight Stick" product sold at newegg and other places selling computer accessories (edit: see bottom for a few options I found on Amazon). I think it will fit on any of the various colors as the casing for the LED stick is the same between them.
You stick these doo-dads on the ends, and it angles the LED stick at 45 degree angle from "flat", ideal if you plan to use the LED stick in a corner and want it angled toward the middle instead of along one edge or another.
I wouldn't recommend to try using the velcro that comes with the stick, not even stuck to the thingy majigers here, or at least don't be surprised if it does not work well. The lights are awesome, the little velcro things they ship with them to mount are not. I am using some glue to stick it in place in my enclosure. This is designed so that you can glue the mount to whatever surface, then the light itself can slide in and out in case the light ever goes out and you have to replace it, you don't have to rip up the mount to do so.
I'm actually using this inside an enclosure for a 3d printer, my Bukobot v2 Duo. Just wire it to the Azteeg x3 board on the 3d printer, and you can send a command to turn the lights on / off when print starts / stops. Personally I have it set to use a custom command in Repetier to turn on/off so I just turn it on when I need it, the lights tend to flicker during prints when there are a lot of back and forth going on by the printer... But still very useful for "before" and "after" the print, and for a few minutes if you are watching the print, with this thing it angles the light right where it needs to be instead of most of the light pointing above the print where it isn't needed.
Print 2 of these things out. Slide them on the ends of the light stick. There is a little groove in the top to allow you to stick the wires on one end through, then slide that end on the little square end of the light stick.
If they do not slide freely on at least one side, use a file one one of them, along the inside. The square ends of the light sticks are slightly tapered so you may need to file down the mount a little. The idea is that you want to be able to slide one end all the way through (so you can take the light out by sliding it past on one end, angle it then slide it out of the other end). If you are super-gluing this to something really flat, you may also want to file the flat part that gets glued, to ensure a flat surface. Super glue bonds on contact, if you don't have a flat surface it doesn't make as good of a bond. See the pictures if it isn't obvious which part to glue to the flat surface.
Slide them on the ends to the light. Make sure the way the light faces is "out" (or facing whatever direction you want it to face), but if not it "shouldn't" be too big a deal as you can slide it out and back in if you realize it faces the wrong way. Now glue the thing into where it is going, only use glue between the flat surface of this thingy, and the surface you are gluing. Do NOT glue the light itself to the mount, it should be held in place pretty well as it is a tight fit. On this thingy, the little notch faces out, away from whatever surface it is being glued to. Also see pictures for examples of how to use.
I found these recently on amazon (Feb 2019), they look identical to the one I have, the main part is the square ends that need to match up with the size of this mount:
You can probably find other colors as well, just make sure the housing looks the same as the ones linked above.