Laticrete SpectraLOCK PRO Premium Grout has all the great features of Laticrete SpectraLOCK PRO grout with enhanced performance. The product has received Greenguard Environmental Institute’s (GEI) certification and is Stainproof (residential applications only). The improved “non-sag” formula is even easier to install while providing attractive, full grout joints. It can be used both interior and exterior on floors and walls. Ideal for re-grouting applications, and is well-suited for wet area applications.