S-400 is a Tile Council of America formula AARII-HT, epoxy mortar and grout that meets or exceeds requirements of ANSI A118.3 and is USDA approved. S-400 is a two-part 100% solids epoxy system designed to resist attacks by many acids, alkalis and other chemical compounds that normally break down cement mortars and grouts. S-400 is sag resistant and should be specified for setting or grouting ceramic tile on any wall or floor installation. S-400 has exceptional bond strength and will remain rigid and cohesive at temperatures up to 350°F.