This is the SAME dye as is sold by Pro Chem but bottled in 1 OUNCE JARS instead of 2 ounce jars.
Washfast Acid Dyes & are designed to permanently dye protein fibers - animal fibers like wool, silk, angora, mohair, alpaca, soy silk, and nylon. They have excellent wash and light fastness properties. Available in over 100 vibrant and intermixable colors. These dyes must be fixed with an acid fixative such as Ammonium Sulfate, Citric Acid Crystals, or white household vinegar.