ASICS Women's GEL-Resolution 2 Tennis Shoe 100% Synthetic leather and synthetic fiber Rubber sole Solyte midsole material is lighter than ASICS' standard EVA and SpEVA, combined with improved cushioning and durability GEL Cushioning Systems attenuate shock during impact phase and toe-off phases PHF (Personal Heel Fit) provides memory foam lined heel collar that molds to athlete's heel, creating personalized fit