Vileda window vac is just ok. When drawing the vac down the window it does unfortunately leave streaks from the serrated rubber. I wish some company would find a way to prevent this from happening. I have tried all ways to stop this but to no avail. Even after finishing and wiping over with a clean microfiber cloth streaks are still very apparent when the Sun shines on the window. A pity as its nice to use. The other thing is the difficulty obtaining spare rubber blades, which you say is obtainable from yourselves but your email from you say that you don't normally deal with the public. They should be able to be bought online from a variety of websites.