EASY TO GRASP: Plastic shell and twistable design make the crayons to be easy to grasp and use, large body (4.5in long and 0.6in thick) is perfect for little fingers. Won't thaw in the water, this bath crayon has a very smooth coloring, even on wet bathtub. EASY TO CLEAN: The bath crayons are designed professionally for bathtub, bath wall or other smooth surface, and we prepared a sponge wipe in barrel. When activity time is over, simply wipe the bathtub with a wet sponge or rinse with showerhead and wash off the color away.it can also be washed off with soapy water if it accidentally gets on the skin or fabric.