Dyeing vessels are containers used in the dyeing process, such as VATS. VATS are large, open-topped containers that are used to hold dye and fabric during the dyeing process. They are usually made of metal or plastic and can be heated to facilitate the dyeing process. The dye is mixed with water and other chemicals in the vat, and the fabric is then immersed in the mixture. The dye is then absorbed by the fabric, resulting in a colored product.