The Superior Pro-Grout Excel line is made up of high-performance, polymer-enhanced, cement-based grouts. They are fast setting, color consistent and feature excellent crack and shrink resistance. Pro-Grout Excel London Fog is a dark grey-brown grout that brings drama as well as durability to your tile design. Use this stain-resistant grout on indoor and outdoor joints 1/16"-1/2" to impede the growth of mold and mildew. Exceeds ANSI A118.7.