This is a waterliner, so it just softens the lower lid a bit and makes a nice clean white line at the bottom.
There are 2 variations of this waterliner, and also 6 color swatches. There is the option to just have the white water line, that comes in two intensities (one for lighter skinned sims and one for darker skinned sims), then the second option is the white water line with the canthus (that pink squishy inner part of your eye), those also come in the two different intensities.
They show up under facepaint. They are for T-E M/F.