I have used this product for over five years. I apply it after I clean our shower glass with A_MAZ Water Stain Remover. This product is a silicon based sealant that fills the microscopic indentations in the glass. It seals the glass and make hard water stain tougher to form. The directions say to apply and wipe off the excess but I leave the excess on. The shower glass looks somewhat cloudy but I think it protects the glass longer.