This chapter explores how one teacher employed 3-D printing technology with fourth-grade students in a STEAM (science, technology, engineering, arts, and mathematics) lab to design and create a prosthetic hand. This project-based unit provided a memorable learning experience. Students were engaged as a class, felt like an integral part of the important mission with which they were tasked, and looked forward to their time each day in the STEAM lab. A materials list, teacher background information, and outcomes are provided. This book selection includes the Table of Contents, Introduction, References, Internet Resources, and Index.