These sponges are the best man can make. They have a white scrubbing side for removing tough grout haze. The scrubbing side of these sponges is bonded with the same material used to bond the heat tiles to the space shuttle.. The reticulated foam of these sponges are super absorbent, clean easier and dry faster. Sponges have rounded corners and edges to prevent grout loss when wiping across joints. I never knew that sponges were so exciting. Sponge measures 4-1/4" Wide x 6-1/2" Long x 2-1/2"