The Shape 1 Stainless Rib, also known as the SS1, 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.
 
The 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.