Watch in amazement as this easy to mix powder expands to make a coloured, thick, "goo" material. When the fun is over, cleaning up couldn’t be easier! Simply add the dissolver sachet to the goo and watch it turn back into water. The Messy Play Gelli Play Tub powder soaks up to 400 times its weight in water. Colour may vary. The Messy Play Gelli Play Tub is great for use in Early Years establishments or for learning about changing materials in Primary Schools, use under adult supervision after appropriate risk assessments have been carried out.