The Challengers are veterans with leg amputations; those who lose their leg are often fit with a prosthetic limb to provide mobility and function. This injury results in a loss of skin surface area, which decreases the body's ability to cool itself, especially when the amputation is above the knee(s). Many individuals remain highly active: continuing to run, hike, and participate in team sports. This high level of activity in combination with the nature of the injury leads to heat and sweat management issues. Sweat can lead to pistoning of the prosthesis, which causes issues with fit and could possibly lead to the prosthesis falling off. Raised skin temperature can also have adverse effects on skin health under and around the prosthesis. The Challenge is to develop a more efficient prosthetic socket cooling system to reduce the skin temperature and sweat in and around the prosthesis.