OOFOS are constructed from a unique and proprietary, closed cell foam — OOFOS named it OOfoam. ... So instead of stressing tired feet and joints after a workout, OOfoam and the patented OOFOS footbed absorb impact. When you're not exercising, OOfoam gives your whole body the opportunity to relax, rebuild and recover. Reduce Stress on Sore Feet, Knees, & Back and Give a New Meaning to Comfort.