The item for sale is 4 Ounces of Sodium Sulfite (Na2SO3), also known as Disodium Sulfite. Sodium Sulfite is a soluble sodium salt of sulfurous acid. It is commonly used as a preservative or to convert elemental halogens to their respective hydrohalic acids. STURDY PLASTIC BOTTLE: Bottles are made of durable Polypropylene Plastic, which is a natural, translucent, lightweight, durable, and chemically resistant copolymer. The screw-top is completely leakproof. Bottle is sealed in plastic with the screw-top shrink-wrapped. HUNDREDS OF USES INCLUDING: Food Preservative / Paper Pulp Treatment / Water Treatment / Oxygen Scavenger Agent / Photographic Processing / Textile Bleaching / Dechlorinization Agent / Froth Flotation / Leather Tanning / Oil Recovery / Chemical Manufacturing / Dye Making.