BAL Rapid-Flex One S1 Tile Adhesive White 20kg (50 Bags)Enhanced with BAL Fibre Strand Technology (FST) for improved flexibility and strength, BAL Rapid Flex One can be grouted after only three hours, and provides extended open time of 30 minutes and pot life of 60 minutes. Available in new white technology and S1 classification, BAL Rapid Flex One can be used on interior or exterior floors and walls to fix most tiles types, most natural stone, terrazzo, rigid foam insulating materials and brick slips.