Porsche Design M Bounce S4 Running Sneaker Shoe - Mens Mesh BOUNCE suspension system returns energy for a smooth, stable run, and offers cushioning and elasticity. Synthetic outsole. Full mesh upper with debossed 3D lines inspired by car aerodynamics. Enhanced leaf-spring suspension system for optimised cushioning. High-tech polymers and carbon plate supplied from automotive industry. Simplified heel unit and optimised spring system for light weight.