You are buying 8 Ounces (by weight) of Calcium Hydroxide. The item is in TWO 8 Fluid Ounce (by volume) Polypropylene bottles. Calcium Hydroxide (Ca(OH)2); also known as Slaked Lime / Builder’s Lime / Cal / Pickling Lime; has hundreds of uses. CAUTION: this is a caustic and corrosive fine powder. Inhalation risk. Bottles are made of sturdy polypropylene. The square, “space-saver” shape ensures that the bottles fit snugly on a shelf. The wide mouth makes for easy dispensing and stackability. To ensure a spill-free journey, the screw tops are heat-sealed and the bottles are sealed in plastic.