It looks like a typical electric vibrator. I am guessing that the spray of water you see is meant to be fluid coming from her genitals (be it lube, urine, "female ejaculate," whatever), but since it's the boxcover art, I'm going to go out on a cynical limb and guess that the image has been enhanced in a PhotoShop-like program to exaggerate what was otherwise probably just a normal amount of squirting/urinating/whatever taking place.
As far as I know, there aren't any vibrators of that particular design-shape which also contain (and can spray) water or other fluids. I'm sure there are vibrating dildos which can do this, not to mention the long list of other sex toys, but the device shown in this picture is (afaik) only ever used for clitoral stimulation (and on rare occasion stimulation of the nipples, as well, for no particular reason other than the guy holding the device thinks it's a good idea).