iDye Poly is for synthetic fibers such as polyester and nylon. It will color almost anything synthetic, including plastics and acrylics, buttons, Frisbee discs, 3D printed objects, toys, dolls, wigs, urethane coatings and more! The dye comes in a dissolvable packet, so there are never any messy powders to handle: simply drop the packet in a pot of water, add your fabric or objects and bring to a boil! For fabric blends containing blended fabrics that contain both synthetic and natural fibers, use iDye Natural with the corresponding iDye Poly color at the same time. Or use a two different complementing colors to create a two-tone effect.