Guardian ShowerGuard – Stop corrosion before it starts. Bathroom glass has many enemies. Hard water, heat, humidity, soap and cleaning agents can corrode glass surfaces and dull their appearance. With ShowerGuard coated glass, homeowners can protect their shower enclosure for years to come. While spray-on treatments eventually wear off, the protection of ShowerGuard coated glass never needs to be reapplied. And unlike other so-called permanent protection products, ShowerGuard coated glass is backed by a robust lifetime limited warranty.