Walking Helper is based on average chest sizes of children 6 months to 4 years old.(11-44 pounds) Vest fits 18 to 28;Material:3 layers of cotton,first layer is pure cotton cloth(good wear properties,anti-scratch and easy to clean.) built-in is high resilient sponge(the pressure on baby will be evenly distribute) third layer:breathable cotton(soft hand feeling and strong air permeability);Fully adjustable design,make babies more comfortable.Baby balances more naturally with hands free,no tugging and twisting on little arms,fewer falls;Reduces back pain from bending over for parents.The width and thickness of the waist stripe allows for a good protection to the kids' waist,parents would focus more on kids' walking.;Note:Hand washing,air dry, do not use washer.To be sure all button in good concatenate before walk