Soft99 Glaco W Jet Strong
Apply this, and rain will bead up and roll down the glass, cleanly taking with it any other water along the way. This high powered aerosol means you can treat even large windscreens in a matter of seconds! …which is useful when you get caught and have to apply in the rain… yes, you can apply this even in the rain! The most convenient hydrophobic glass coating imaginable!