Shape 1 is a traditional kidney-shaped rib, probably the most universally recognized pottery tool. It fits well in the hand and is useful for sculpting, hand building and throwing clay. Shape 1 is not too big, not too small. It's just right. All of the Mudtools stainless steel ribs are made of cutlery-grade stainless steel and have varying flexibility among the tool styles. The Shape 1 Stainless Rib is also available in various polymers.