Ultimate FAST Grout Sealer - Designed for immediate application to damp, uncured floor and wall grout while leaving no hard-to-remove residue, can also be used on clean, existing grout and will not change any surface appearance. Seal immediately after grouting for the ultimate stain protection. This new AC Technology provides unmatched protection for grout, natural stone, masonry, and concrete while the ‘inverted’ anyway valve allows for application onto both horizontal and vertical surfaces from a standing position. It penetrates to protect against both oil and water-based stains while still allowing the treated surface to breathe.