Brand new. Box only opened to take photo of what's inside. I think this stuff is brilliant!! I bought several boxes of this DS40 for our semi blocked microbore central heating system. It worked a treat and I would highly recommend it. It's a fast acting Fernox DS40 descaler & cleaner is a citric acid based cleaner used to effectively remove limescale, magnetite and black sludge. Apparently it's being discontinued. Now selling the excess boxes that I bought in. Please see instructions on how to use in the attached photos. Both the cleaner and neutraliser are powdered and easily dissolve in water.