- Both lightweight and flexible, the GEL-GAME 9 tennis shoe is versatile for all-court players. Preserving its excellent support properties, our focus this season was to improve the shoe's ventilation and flexibility. Featuring an open mesh design on the upper to improve airflow and keep feet cool, this shoe is complemented with synthetic leather overlays and a PU (polyurethane) film that offers improved stability when making abrupt transitions. The TRUSSTIC technology in the midsole generates better stability on the court. At the same time, the new tooling combines an EVA midsole foam with GEL technology cushioning in the forefoot to increase shock absorption. Additionally, the improved outsole offers better flexibility and a more durable design.