After applying the next rain was clear - as described here - until 100 km / h shows the effect. The larger the droplet, the better you will be blown away by the wind. However whirled water from traveling ahead cars remains as a fine veil on the disc. Already with 90 km / h takes the effect significantly. So no use in the city, since no effect. Big disadvantage: When using the wiper there streaks, which are very annoying particularly in the dark. Conclusion: Once and never again!
