This system Magical Vileda comprises a water repellent spray of 500ml and a micro fiber. Operation is simple: you spray on your surfaces then you dry with the micro fiber. I did the test this in my shower by not applying as a shower walls to see the difference. I followed the instructions of the product which, to my surprise, did not specify to clean surfaces before application. The micro-fiber is supposed to be sufficient. Indeed, it removes soap scum, but if like me you live in an area where the water is very hard, I recommend you spend a limescale before using this product Vileda because it will not come to end (though I clean my walls every week). The application is easy, but be careful not to put too much product because if poorly wiped, it leaves slightly whitish streaks which are seen on the transparent walls and mirrors. So much for the application. Regarding the result, I find it quite convincing: water does not stagnate on the treated surfaces, they run off carrying with them the projections of soap and shampoo, so less dirt and lime deposits. Even the fog is not formed, very convenient on the mirrors. After 10 days, the water repellent power is still visible on my wall treated, which remains clean (besides my limescale remaining to the application). The difference with the untreated wall is very clear (soap splashes, streaks whitish limestone). 4 stars and not 5 so as this product is effective against re-statements, but they are not an "all-in-one" since it does not eliminate the limestone.