I found it on TKBTrading.com, which is a site that sells everything people need to mix and package their own cosmetics. Although they call this "Mineral Wetliner" online and show a plain white bottle in the picture, when you order it, the above pictured bottle is what you get in the mail. You can get 1 bottle of .5 oz worth of solution for $8.00 or a set of 6 for $26.00. I opted for the set of 6 since it was a better deal.
As you can see, the bottle is sort of like an eyedropper bottle, which makes it very easy to work with--you just squeeze out a few drops for what you need and you're done--no mess. The liquid is clear on its own. You can use it to seal your eyeliner, foil loose shadows (which is turning loose shadows into a wet solution to use as a liner or to make the color pop more) and it also makes a great glitter adhesive. You can also use it to revive dried out cream/gel liners: just squeeze a few drops into your liner pot, use a mixing spatula or an orange stick to stir everything together and, voila!
In the pictures below, I thought I would demonstrate how good it is at sealing liner and keeping it smudge proof.
This is that same swatch after I rubbed it back and forth a zillion times with a damp finger. Pretty impressive, huh?
Below, I used the iLine to foil an NYX Pearl Mania loose shadow (Jade Green Pearl if I recall correctly)...
The solution really brings out the vibrancy of whatever shadow you mix it with and makes it like liquid metal.
The one thing you need to be aware of with this stuff: it dries pretty fast once mixed. If you are using it just to line with a loose shadow, I suggest squeezing a few drops into the dropper bottle's cap, dipping your liner brush into that, then into your chosen shadow and applying it that way. If you're foiling a larger amount of shadow, you can use the cap as a tiny mixing pot by squeezing some solution into it and then adding shadow (I find that mixing it in the bottle's cap, rather than something that is flat and more open, slows the drying process). I just rinse the cap out with hot water and dry it before I put it back on the bottle.
To sum it up, I'd much rather pay $26.00 for six of these than pay the same price for only one tiny bottle of a high-end mixing medium. It works beautifully, has tons of uses, comes in smart, easy to use packaging...really, what's not to love?
Do you ever foil or line with loose shadows? What do you use?