SPECTRUM 930 Patina Acid Stain is a ready to use, penetrating product that reacts with concrete to produce a unique and permanent coloured surface. Unlike other colourants, SPECTRUM 930 Patina Acid Stain penetrates the concrete surface to produce the aged appearance of timeworn patina. The colour will last as long as the concrete surface remains intact. SPECTUM 930 Patina Acid Stain is available in a variety of colours and creates an antique coloured finish when applied to concrete.