The Asics Gel-Cumulus™ 21 road running shoes are designed to cushion and support your feet over long distances. FLYTEFOAM™ Propel technology provides optimal bounce and energy. Rear and forefoot GEL™ technology offers a premium level of shock absorption. GUIDANCE LINE™ technology enhances gait efficiency and an internal heel counter keeps your foot in position. Impact Guidance System technology enhances your natural gait. EVA sockliner moulds to the shape of your feet for increased comfort. High resistant AHAR™ limits wear at key impact areas. Engineered jacquard mesh upper keeps your feet cool. Reflective details on the outside of the shoe provides increased visibility.Upper: Synthetic. Sole: Rubber.