One of the more difficult tasks encountered in engineering design is the most appropriate material to use for a specific application. Engineering designers generally make their material choices based upon previous experiences. They prefer familiar materials but will consider unfamiliar options if they will meet the requirements. The ideal material choice will become identified when a number of factors are resolved as the selection process is developed. The physical properties of a metallic material used for structural purposes are determined from experimental testing. The maximum compressive stress a material specimen is capable of carrying is known as the ultimate compressive stress. Stiffness is the ability of a material to maintain its shape when subject to a load or force. The material properties will generally be listed on a company database covering all the materials used across the company's product lines, and it becomes a simple task to isolate a suitable material that closely fits the operating requirements criteria.