Rain?X Shower Door Water Repellent Rain?X Shower Door Water Repellent uses advanced technology that causes water to bead and slide off on glass surfaces. Regular use helps prevent hard water stains, soap scum and grime build-up on your glass shower door ? keeping it looking clean for weeks! Helps to prevent soap scum, hard water deposit and grime from building up and sticking onto shower doors. Product Features For glass surfaces only Easy-to-apply, durable coating lasts for weeks!