AEROSIL® R 974 W is a hydrophobic fumed silica after treated with DDS (Dimethyldichlorosilane) based on a hydrophilic fumed silica with a specific surface area of 200m²/g. The product thickening efficiency of AEROSIL® R 974 W ex RHE is consistent with the Waterford-produced AEROSIL® R 974. This profile is different than the thickening profile of standard RHE quality.