Engineered mesh provides ventilation for your forefoot while supporting your midfoot. The partial mesh inner sleeve enhances breathability while offering and a sock-like fit. Balenciaga Speed Trainer Stretch Knit Runner Sock Black White New With Box Balenciaga For Sale. Plush foam and mesh tongue for breathable comfort and Midsole flex grooves provide greater forefoot flexibility Balenciaga Speed Trainer Waffle outsole for durability and great multi-surface traction.