Under Armour Spine Venom Running Shoes Synthetic-and-mesh UA Spine Chassis Technology - Creates an incredibly light, flexible feel without sacrificing support. Micro G Foam - Encapsulated within the chassis delivers unrivaled rebound and energy return. Breathable Mesh Upper - With an underlying MPZ structure for protection and lightweight support. TPU Heel Counter - For greater stability without being too rigid for comfort. Full-Length Moulded 4D Foam Sockliner and Collar - Conform to your foot's exact shape, eliminating slippage.