Shape 1 is the traditional kidney-shaped rib. Probably the most universally recognised pottery tool. It fits well in the hand and is useful for sculpting, hand building and throwing clay. Shape 1 is no too big. Not too small. It is just right. Mudtools stainless steel ribs are all made of cutlery grade stainless steel with varying flexibility among the tool styles. This same shape is also available in various polymers.