Harmony acid stain is a liquid based on acid and inorganic pigments to stain an existing screed or porous slab. Colouring takes place by chemiocal reaction, producing rich, vibrant shades that resemble natural mineral colours. Harmony acid stain remains stable over time and withstands sunlight for many years. Strong pointsrnsuitable for indoor and outdoor use. colurs new or old concretes durablyrndecorative effects by chemical reactionrninexpensive.