The shoe itself is from a manufacturer in China so the size is based on UK sizing, it is a size 20 UK which is 5 3/4 inches in sole length by 2 1/2 inches at the widest point of the foot (roughly 18mo.-24mo.). The material is cotton, and the soles are a hard rubber.
I recommend hand washing these only to keep them looking their best. I usually just give them a wipe with a damp cloth and they are as good as new! My daughter has a pair I've made for her and they have held up just fine. =)
Please measure your childs foot so that you are sure they will fit. I will not be accepting returns on sizing issues since all the information is posted regarding that. So again please be sure your child will be able to fit the shoe.