I've tried a few sprays of this kind. The result was often very unsatisfactory. Even with this spray, I was very skeptical. But from the result I am but then pleasantly surprised. It works. I have tested it, as I have poured water over the Goretex hiking boots. The water is then abgeperlt. To me, the evidence that this medication works. However, one must have at least 2 times the shoes, better 3 times Spray In order to achieve this effect. The Impregnierspray is applied by pumping technology (quite strenuous). For environmental reasons Solitaire want to do without propellants. For me quite cynical in this toxic stuff. All I know Impregniersprays are quite toxic and should only be applied outdoors. But this means acting halt and I have to date still can not find anything better.