Xion Knee-Shins Pro Evo – D3OThe XION Protective Gear Knee shin protectors PRO EVO are specifically designed to wear as an undergarment. The product is sold as a pair to cover both knees. An ideal replacement of the traditional bulky rigid protection. The pads are removable, flexible and breathable. A revolutionary material called D3O (dee three oh) which is made of Intelligent Molecules that flow with you as you move but on shock impact lock together (in a fraction of a second)