Duo Blast with Reactor Technology mold and mildew remover. Innovative chemistry mixes as it is sprayed, harnessing a powerful reaction to remove tough embedded stains on most surfaces inside and out. Ideal for restoring the look of hard surfaces like: bathroom tiles and grout, lumber and drywall, and concrete and cinder block. Does not destroy the look of fabric, cushions, patio furniture, and more. Biodegradable.