Chuaed, car wax works that way. It beads water so it will easily flow off.

The windshield repellant is only different in that it is clear. You can wax your windshield if you want, just make sure you completely buff it off after letting it dry. It has the same effect. Buff with a clean towel para walang streaks. Make sure you also look through the glass from inside the cabin so you can see kung may streaks or not. This is the best way to avoid streaks when you least need them like when driving towards the sun/west.