RIT ColourStay Dye Fixative is an after-dye treatment used to help set colour on fabrics you have dyed at home when you want extra help keeping dye in place. This 236 mL (8 fl oz) bottle is applied after dyeing to improve washfastness on common cellulose fibers and many blends after using home dye methods on garments and decor. Use as directed before the first wash, then launder separately to help reduce bleeding and transfer over time.