RESI SHIELD GLASS & SURFACE PROTECTANT durably seals the microscopic pores of the surface to actively repel water, soil & stains for easy removal. It provides a repellent finish that dramatically reduces the adhesion & build-up of dirt, grime, water spots, limescale, rust, soap scum & hard water minerals for easier next-time cleaning. It is extremely durable and can last for up to 5 years on most exterior glass surfaces. Like all coatings or paints, durability is dependent upon the initial application, degree of exposure, maintenance and the ongoing abrasion to surface. It can be easily renewed without removing the prior coating to rejuvenate and refresh its shielding and protective benefits.