A rain repellent is a special product that is designed to be applied on glass. The product leaves a very hydrophobic layer on top of the glass. Water won't be able to form any wetting, and the round beads are more easily blown off the glass.
How to Detail a Car
A guide into dilution ratios - DetailingWiki, the free wiki for detailers
DetailingWiki, the free wiki for detailers
Using a rain repellent - DetailingWiki, the free wiki for detailers
What is road spray - DetailingWiki, the free wiki for detailers
What is an all purpose cleaner (APC) - DetailingWiki, the free wiki for detailers
what is a spray wax - DetailingWiki, the free wiki for detailers
What is a paint protection film - DetailingWiki, the free wiki for detailers
Using a rain repellent - DetailingWiki, the free wiki for detailers
The best product - DetailingWiki, the free wiki for detailers
How to wrap - DetailingWiki, the free wiki for detailers
What is an emulsion - DetailingWiki, the free wiki for detailers
Wax before sealants, or sealants before wax - DetailingWiki, the free wiki for detailers
Engine bay cleaning - basic - DetailingWiki, the free wiki for detailers
Rain‑X 2-IN-1 Exterior Detailer and Water Repellent is a convenient way to keep your car looking good between washes while protecting the surface from
Rain-x 2-in-1 Exterior Detailer and Water Repellent 23 FL OZ - 620115