ASICS Women's GEL-Challenger 7 Tennis Shoe 100% Synthetic and mesh Rubber sole GEL Cushioning System attenuates shock during impact phase and toe-off phases PGuard toe protector enhances toe durability PHF (Personal Heel Fit) features a Memory foam lined heel collar that molds to the athlete's heel, creating a personalized fit Solyte midsole material is lighter than ASICS' standard EVA and SpEVA, combined with improved cushioning and durability