The GEL-CUMULUS® 21 blends two different midsole foams - one for lightweight softness and another that adds a more responsive step. It also has rear and forefoot GEL® technology for premium level shock absorption. GUIDANCE LINE™ technology helps create a more efficient stride, while the internal heel counter holds your foot in position for added support. The shoe helps align your stride with smoother propulsion while a contoured EVA sockliner better matches the shape of your feet for added comfort. The durable outsole reduces wear at key impact areas and the engineered jacquard mesh upper helps keep the top of the foot cool. Reflective details on the outside of the shoe also promote better visibility in low-light settings.