AM Rain - Window Rain Repellent £10.00 Quantity: at £10.00 each AM Rain is an easy to apply rain repellent for all exterior windows. This product will leave an invisible hydrophobic layer that repels water to provide clearer and safer vision. Directions: Apply to clean, dry glass using a microfibre, allowing 15 minutes between applications. AM Rain will provide protection for up to 2 months. Remove excess residue using AM Glass.