HOKA ONE ONE Men's M Challenger ATR 2 Running Shoe synthetic-and-mesh Open Mesh Upper - Promotes breathability, ensuring air can reach all confinements of the feet. Seamless Supportive Overlays - Provide security around the midfoot whilst simultaneously reducing weight. Traditional Lacing System - Increases the fit of the shoe promoting a more secure fit. Early Stage Meta-Rocker Geometry - Specifically engineered with a low heel-toe differential and a sculpted outsole radius in the heel and toe, encourages a guided foot gait cycle; supports a runner's form and running mechanics. CMEVA midsole - Providing industry leading cushioning for increased impact protection and stability.