Hummel Ballet Shoes Childrens. Hummel Junior Gymnastics Slippers. The Hummel junior gym shoe is made of a soft material and has a durable, non-slip rubber sole. It has no laces; instead it has a herringbone elastic band for an easy fit while keeping your child's little feet in place. Flexible materials, flexible and comfortable fit, durable, non-slip rubber outsole, elastic band with chevrons.